› uploads › 1 › ... polynomial functions - mathematics vision projectalgebra ii // module 4...
TRANSCRIPT
The Mathematics Vision Project Scott Hendrickson, Joleigh Honey, Barbara Kuehl, Travis Lemon, Janet Sutorius
© 2018 Mathematics Vision Project Original work © 2013 in partnership with the Utah State Office of Education
This work is licensed under the Creative Commons Attribution CC BY 4.0
MODULE 4
Polynomial Functions
ALGEBRA II
An Integrated Approach
Standard Teacher Notes
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
MODULE 4 - TABLE OF CONTENTS
POLYNOMIAL FUNCTIONS
4.1 Scott’s March Madness – A Develop Understanding Task Introduce polynomial functions and their rates of change (F.BF.1, F.LE.3, A.CED.2) Ready, Set, Go Homework: Polynomial Functions 4.1
4.2 You-mix Cubes – A Solidify Understanding Task Graph ! = #$ with transformations and compare to ! = #%. (F.BF.3, F.IF.4, F.IF.5, F.IF.7) Ready, Set, Go Homework: Polynomial Functions 4.2
4.3 Building Strong Roots – A Solidify Understanding Task Understand the Fundamental Theorem of Algebra and apply it to cubic functions to find roots. (A.SSE.1, A.APR.3, N.CN.9) Ready, Set, Go Homework: Polynomial Functions 4.3
4.4 Getting to the Root of the Problem – A Solidify Understanding Task Find the roots of polynomials and write polynomial equations in factored form. (A.APR.3, N.CN.8, N.CN.9) Ready, Set, Go Homework: Polynomial Functions 4.4
4.5 Is This the End? – A Solidify Understanding Task Examine the end behavior of polynomials and determine whether they are even or odd. (F.LE.3, A.SSE.1, F.IF.4, F.BF.3) Ready, Set, Go Homework: Polynomial Functions 4.5
4.6 Puzzling Over Polynomials – A Practice Understanding Task Analyze polynomials, determine roots, end behavior, and write equations (A-APR.3, N-CN.8, N-CN.9, A-CED.2) Ready, Set, Go Homework: Polynomial Functions 4.6
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.1 Scott’s March Madness
A Develop Understanding Task
Eachyear,Scottparticipatesinthe“MachoMarch”promotion.The
goalof“MachoMarch”istoraisemoneyforcharitybyfinding
sponsorstodonatebasedonthenumberofpush-upscompleted
withinthemonth.Lastyear,Scottwasproudofthemoneyhe
raised,butwasalsodeterminedtoincreasethenumberofpush-
upshewouldcompletethisyear.
PartI:RevisitingthePast
BelowisthebargraphandtableScottusedlastyeartokeeptrackofthenumberofpush-upshe
completedeachday,showinghecompletedthreepush-upsondayoneandfivepush-ups(fora
combinedtotalofeightpush-ups)ondaytwo.Scott
continuedthispatternthroughoutthemonth.
1 2 3 4
1. Writetherecursiveandexplicitequationsforthenumberofpush-upsScottcompletedonany
givendaylastyear.Explainhowyourequationsconnecttothebargraphandthetableabove.
?Days A(?)
Push-ups
eachday
E(?)
Totalnumberof
pushupsinthe
month
1 3 32 5 83 7 154 9 245 11 35… … ?
CC
BY
US
Arm
y O
hio
http
s://f
lic.k
r/p/
fxuN
zc
1
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
2. Writetherecursiveandexplicitequationfortheaccumulatedtotalnumberofpush-ups
Scottcompletedbyanygivendayduringthe“MachoMarch”promotionlastyear.
PartII:MarchMadness
Thisyear,Scott’splanistolookatthetotalnumberofpush-upshecompletedforthemonthlastyear
(g(n))anddothatmanypush-upseachday(m(n)).
3. Howmanypush-upswillScottcompleteondayfour?Howdidyoucomeupwiththisnumber?
Writetherecursiveequationtorepresentthetotalnumberofpush-upsScottwillcompletefor
themonthonanygivenday.
4. Howmanytotalpush-upswillScottcompleteforthemonthondayfour?
?Days A(?)
Push-upseach
daylastyear
E(?)
Totalnumber
ofpushupsin
themonth
N(?)
Push-upseach
daythisyear
T(n)
Totalpush-ups
completedfor
themonth
1 3 3 3 2 5 8 8 3 7 15 15 4 9
24 5 … … ?
2
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
5. Withoutfindingtheexplicitequation,makeaconjectureastothetypeoffunctionthatwould
representtheexplicitequationforthetotalnumberofpush-upsScottwouldcompleteonany
givendayforthisyear’spromotion.
6. Howdoestherateofchangeforthisexplicitequationcomparetotheratesofchangeforthe
explicitequationsinquestions1and2?
7. Testyourconjecturefromquestion5andjustifythatitwillalwaysbetrue(seeifyoucanmove
toageneralizationforallpolynomialfunctions).
3
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.1 Scott’s March Madness – Teacher Notes A Develop Understanding Task
Purpose:Thepurposeofthistaskistodevelopstudentunderstandingofhowthedegreeofa
polynomialrelatestotheoverallrateofchange.Lastyear,studentswhodidthetaskScott’sMacho
Marchdiscoveredthatquadraticfunctionscanbemodelsforthesumofalinearfunction,whichcreates
alinearrateofchange.Thisyear,studentswillseethatcubicfunctionscanbemodelsforthesumofa
quadraticfunction.Question7promptsstudentstomakeaconjectureandtomovetothe
generalizationthatthesumofapolynomialofdegreenwillproduceapolynomialofthedegreen+1.In
thistask,studentshavetheopportunitytousealgebraic,numeric,andgraphicalrepresentationsto
modelastorycontextandmakeconnections.
CoreStandardsFocus
F-BF.1Writeafunctionthatdescribesarelationshipbetweentwoquantities.*
a. Determineanexplicitexpression,arecursiveprocess,orstepsforcalculationfromacontext.
b. Combinestandardfunctiontypesusingarithmeticoperations.Forexample,buildafunctionthat
modelsthetemperatureofacoolingbodybyaddingaconstantfunctiontoadecayingexponential,
andrelatethesefunctionstothemodel.
F.LE.3Observeusinggraphsandtablesthataquantityincreasingexponentiallyeventuallyexceedsa
quantityincreasinglinearly,quadratically,or(moregenerally)asapolynomialfunction.
A.CED.2(Createequationsthatdescribenumbersorrelationships)Createequationsintwoormore
variablestorepresentrelationshipsbetweenquantities;graphequationsoncoordinateaxeswith
labelsandscales.
RelatedStandards:F.IF.9,A.CED.1
ThistaskalsofollowsthestructuresuggestedintheModelingstandard:
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
StandardsforMathematicalPractice:
SMP1–Makesenseofproblemsandpersevereinsolvingthem
SMP2–Reasonabstractlyandquantitatively
SMP7–Lookforandmakeuseofstructure
SMP8–Lookforexpressregularityinrepeatedreasoning
TheTeachingCycle:
Launch:
Beginthetaskbysettingupthescenarioandclarifyingthetaskstartswiththenumberofpush-ups
Scottcompletedlastyearduringtheeventandthenmovesintothenumberofpush-upsheintendsto
completethisyear.Questions1and2fromthetaskmaybefamiliarforstudentsfromSecondaryI
(Scott’sWorkout)andSecondaryII(Scott’sMachoMarch).Youmaywishtohavestudentsworkon
questiononeasawarm-uptodiscusspriortodoingtherestofthetask.
Explore:
Havestudentsworkindependentlyforawhilebeforetheyworkwithapartner.Monitorstudent
thinkingastheywork.Sincestudentsshouldbefamiliarwithrepresentationsforlinearfunctions,do
notallowanygrouptospendtoomuchtimeonquestion1(youmayevenwishtomakethisa‘warm-
up’questioninsteadofpartofthetask).Question2isalsoreviewbutismoredifficult.Lettingstudents
workthroughthiswillbevaluabletowardmakingconnectionsandansweringthequestionsinPartII.
Forthosestudentswhohaveahardtimegettingstarted,encouragethemtouseanotherrepresentation
(visualmodel,table,orgraph)tohelpwritetheequations(bothexplicitandrecursive)astheyworkon
thetask.Question2answers:Recursive:E(1) = 3, E(?) = E(? − 1) + (2? + 1);Explicitequation
(whensimplified):E(?) = ?(? + 2).ThewholegroupdiscussionwillfocusonthequestionsfromPart
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
II,solookforthosewhomakeconjecturesthatmatchthepurposeofthetask.Itwillbehelpfultohave
studentswhosharetousethevisualmodeltheycreatedtoexplainhowtheyfoundsolutionsandmade
conjectures.Forexample,atableshowingthedifferencecolumnsimilartotheoneintheanswerkey
(solution3)toshowthatcubicfunctionscanbemodelsforthesumofaquadraticfunction--justas
quadraticfunctionscanbemodelsforthesumofalinearequation.
Discuss:
Startthewholegroupdiscussionbyhavingagroupgothroughtheirprocessforansweringquestions2,
3and4(besuretohavethemshowthemodeltheyused-visualdiagram,table,orgraph).Ifpossible,
haveanothergroupsharetheirvisualmodeliftheyusedadifferentrepresentation(atablehighlights
thedifferencecolumnwhereasamodeloragraphvisuallyhighlightstheratesofchangeoftheexplicit
equations).
Afterstudentssharetheirstrategiesforcompletingquestions2-4,movethediscussiontothelastthree
questionsinthetask(questions5-7).Thesequestionsfocusonthetotalnumberofpush-upscompleted
forthemonth,orinotherwords,thecubicrateofchangecreatedasaresultofaddingtheexplicit
quadraticfunctiontocurrentnumberofpush-upscompletedonanygivenday.Thegoalforthisportion
ofthediscussionisforstudentstosummarizethekeypointsthatreflectthepurposeofthistask*.
Observationstobemade:
• Thefirstdifferenceisquadratic,theseconddifferenceislinearandthethirddifferenceis
constant(acharacteristicofacubicfunction).
• Thegraph“curves”(growsatafasterrate)morethanthatofaquadratic(Thisalsohelps
forfutureworkregardingratesofchangeofpolynomialfunctionsversusthatofexponential
functions:whilecubicfunctionsgrowatafasterratethanquadratics,theyarenotasfastas
exponential,whosethirddifferenceisstillexponential).
• Cubicfunctionscanbemodelsforthesumofthetermsofaquadraticfunctioninthesame
waythatquadraticfunctionscanbemodelsforsumoftermsofalinearfunction.(Thisis
similartotherelationshipfromtheSecondaryIItaskScott’sMachoMarchwherestudents
discoveredthatquadraticfunctionscanbemodelsforthesumofalinearfunction,which
createsalinearrateofchange.)
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
• Recognizethereisarelationshipofthedegreeofapolynomialandtheoverallrateof
change.(Generalization:whenthenthdifferenceisconstant,thenthepolynomialisof
degreen).
• Makeaconjecturethatthesumofapolynomialofdegreenwillproduceapolynomialofthe
degreen+1.
*Ifstudentsstruggletocomeupwiththeaboveobservations,havethemfocusonthedifference
columnsandcomparethethreerecursiveequationsfromquestions1,2,and3(whoseequations
representtheformervalueplusaconstantterm,alinearexpression,andaquadraticexpression
respectively).Askstudentstoidentifysimilaritiesanddifferences.Theimportantthingtonoticeisthat
thechangeinthefunctionistheexpressionaddedtotherecursiveformula.Iftherateofchangeisa
constant,thenthefunctionislinear.Ifthechangeisalinearexpression,thenthefunctionisquadratic.
Ifthechangeisaquadraticexpression,thenthefunctioniscubic.
**Iftimepermits,itisalwaysgoodtoreviewanddiscussfeaturesoffunctions.Inthistask,thefunction
todescribethetotalnumberofpush-upsScottwouldcompletewouldbeagooddiscussionfor
domain/range,wherethesituationisincreasing/decreasing,intercepts,whetherthefunctionis
discreteorcontinuous,andthe‘endbehavior’.Whilethedomainisrestrictedtothenumberofdaysin
March,thisisagoodexampleofdistinguishingbetweentherangeofthesituationversustheend
behavioroftheactualfunction.
AlignedReady,Set,Go:PolynomialFunctions4.1
ALGEBRA 2// MODULE 4
POLYNOMIAL FUNCTIONS – 4.1
4.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
READY Topic:Completinginequalitystatements
Foreachproblem,placetheappropriateinequalitysymbolbetweenthetwoexpressionstomakethestatementtrue.If! > #, %ℎ'(: *+- > 10, %ℎ'(: *+0 < - < 1
1. 3!____3#
4.-3____25
7.-____-3
2. # − !____! − #
5.√-____-3
8.√-____-
3.! + -____# + - 6.-3____-9 9.-____3-
SET Topic:Classifyingfunctions
Identifythetypeoffunctionforeachproblem.Explainhowyouknow.10
- +(-) 1 3 2 6 3 12 4 24 5 48
11.- +(-) 1 3 2 6 3 9 4 12 5 15
12.- +(-) 1 3 2 9 3 18 4 30 5 45
13.- +(-)1 72 93 134 215 37
14.- +(-)1 -262 -193 04 375 98
15.- +(-)1 -42 33 184 415 72
16.WhichoftheabovefunctionsareNOTpolynomials?
READY, SET, GO! Name PeriodDate
4
ALGEBRA 2// MODULE 4
POLYNOMIAL FUNCTIONS – 4.1
4.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
GO Topic:Recallinglongdivisionandthemeaningofafactor
Findthequotientwithoutusingacalculator.Ifyouhavearemainder,writetheremainderas
awholenumber.Example: remainder217.
18.
19.Is30afactorof510?Howdoyouknow?
20.Is13afactorof8359?Howdoyouknow?
21.
22.
23.Is22afactorof14587?Howdoyouknow?
24.Is952afactorof40936?Howdoyouknow?
25.
26.
27.Is92afactorof3405? 28.Is27afactorof3564?
21 1497
30 510 13 8359
22 14857 952 40936
92 3405 27 3564
5
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.2 You-mix Cubes A Solidify Understanding Task
InScott’sMarchMadness,thefunctionthatwasgeneratedby
thesumoftermsinaquadraticfunctionwascalledacubicfunction.Linearfunctions,
quadraticfunctions,andcubicfunctionsareallinthefamilyoffunctionscalledpolynomials,
whichincludefunctionsofhigherpowerstoo.Inthistask,wewillexploremoreaboutcubic
functionstohelpustoseesomeofthesimilaritiesanddifferencesbetweencubicfunctionsand
quadraticfunctions.
Tobegin,let’stakealookatthemostbasiccubicfunction,!(#) = #& .Itistechnicallyadegree3polynomialbecausethehighestexponentis3,butit’scalledacubicfunctionbecausethese
functionsareoftenusedtomodelvolume.Thisislikequadraticfunctionswhicharedegree2
polynomialsbutarecalledquadraticaftertheLatinwordforsquare.Scott’sMarchMadness
showedthatlinearfunctionshaveaconstantrateofchange,quadraticfunctionshavealinearrate
ofchange,andcubicfunctionshaveaquadraticrateofchange.
1. Useatabletoverifythat!(#) = #&hasaquadraticrateofchange.
2. Graph!(#) = #& .
CC
BY
Ste
ren
Gia
nnin
i
http
s://f
lic.k
r/p/
7LJfW
C
6
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
3. Describethefeaturesof!(#) = #&includingintercepts,intervalsofincreaseordecrease,domain,range,etc.4. Usingyourknowledgeoftransformations,grapheachofthefollowingwithoutusingtechnology.
a) !(#) = #& − 3 b) !(#) = (# + 3)&
c) !(#) = 2#& d) !(#) = −(# − 1)& + 2
5. Usetechnologytocheckyourgraphsabove.Whattransformationsdidyougetright?What
areasdoyouneedtoimproveonsothatyourcubicgraphsareperfect?
7
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
6. Sincequadraticfunctionsandcubicfunctionsarebothinthepolynomialfamilyoffunctions,
wewouldexpectthemtosharesomecommoncharacteristics.Listallthesimilaritiesbetween
!(#) = #&and,(#) = #- .
7. Asyoucanseefromthegraphof!(#) = #& ,therearealsosomerealdifferencesincubicfunctionsandquadraticfunctions.Eachofthefollowingstatementsdescribeoneofthose
differences.Explainwhyeachstatementistruebycompletingthesentence.
a) Therangeof!(#) = #&is(−∞,∞),buttherangeof,(#) = #-is[0, ∞)because:_______________________________________________________________________________________________________
b) For# > 1, !(#) > ,(#)because:_______________________________________________________________________________________________________________________________________________________________
c) For0 < # < 1, ,(#) > !(#)because:__________________________________________________________________________________________________________________________________________________________
8
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.2 You-mix Cubes – Teacher Notes A Solidify Understanding Task Purpose:
Thepurposeofthistaskistoexamineandextendideasaboutcubicfunctionsthatweresurfacedin
3.1Scott’sMachoMarchMadness.Studentsconsiderthebasiccubicfunction,!(#) = #& ,identifying
itscharacteristicsandgraph.Studentswillrecognizethatthegraphof!(#) = #&canbe
transformedusingthesametechniquesasquadraticfunctions.Studentswillalsomakeother
comparisonsbetweencubicandquadraticfunctions,specifically,theirendbehaviorandthevalues
ofeachfunctionwhen#isafraction.
CoreStandardsFocus:
F.BF.3Identifytheeffectonthegraphofreplacingf(x)byf(x)+k,kf(x),f(kx),andf(x+k)forspecific
valuesofk(bothpositiveandnegative);findthevalueofkgiventhegraphs.Experimentwithcases
andillustrateanexplanationoftheeffectsonthegraphusingtechnology.Includerecognizingeven
andoddfunctionsfromthegraphsandalgebraicexpressionsforthem.
F.IF.4.Forafunctionthatmodelsarelationshipbetweentwoquantities,interpretkeyfeaturesof
graphsandtablesintermsofthequantities,andsketchgraphsshowingkeyfeaturesgivenaverbal
descriptionoftherelationship.Keyfeaturesinclude:intercepts;intervalswherethefunctionis
increasing,decreasing,positive,ornegative;relativemaximumsandminimums;symmetries;end
behavior;andperiodicity.
F.IF.5.Relatethedomainofafunctiontoitsgraphand,whereapplicable,tothequantitative
relationshipitdescribes.Forexample,ifthefunctionh(n)givesthenumberofperson-hoursittakes
toassemblenenginesinafactory,thenthepositiveintegerswouldbeanappropriatedomainfor
thefunction.
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
F.IF.7:Graphfunctionsexpressedsymbolicallyandshowkeyfeaturesofthegraph,byhandin
simplecasesandusingtechnologyformorecomplicatedcases.
a.Graphlinearandquadraticfunctionsandshowintercepts,maxima,andminima.
c.Graphpolynomialfunctions,identifyingzeroswhensuitablefactorizationsareavailable,
andshowingendbehavior.
RelatedStandards:A.SSE.1
StandardsforMathematicalPractice:
SMP2–Reasonabstractlyandquantitatively
SMP8–Lookforexpressregularityinrepeatedreasoning
Vocabulary:cubicfunction,polynomialfunction,degreeofapolynomial
TheTeachingCycle:
Launch:
Beginthetaskbytellingstudentsthatthecubicfunctionsintroducedintask3.1Scott’sMacho
MarchMadnessandthequadraticandlinearfunctionsthattheyhavepreviouslyworkedwithallfall
intothefamilyofpolynomialfunctions.Atechnicaldefinitionofpolynomialisgivenlater,buta
workingdefinitionisthatapolynomialfunctionisasumoftermsinthesamevariablewiththe
naturalnumberexponentsandrealcoefficients.Demonstrateforstudentshowtoidentifythe
degreeofthepolynomialbasedonthehighest-poweredterm:
Degree1Polynomial(LinearFunction):S = 3# − 1
Degree2Polynomial(QuadraticFunction):S = 3#- − 2# + 9
Degree3Polynomial(CubicFunction):S = −5#& + 3#- − 10# + 6
Degree4Polynomial(QuarticFunction):S = #W + 7#& − 4#- − 24# + 1
Explainthatinthistask,wewillbeintroducingmoreofthecharacteristicsofcubicfunctionsand
comparingthemtowhatweknowaboutquadraticfunctions.
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Explore:
Monitorstudentsastheyareworkingonthetasktoseethattheyarecreatinganorganizedtableof
valuesthatcanbeusedthroughoutthetask.Inthetableforproblem#1,itiseasiesttoshowthe
quadraticrateofchangestartingfrom0andlookingatwholenumbervalues.Ifstudentsarestuck,
encouragethemtostartthere.Eventually,theywillneedtoconsiderbothpositiveandnegative
numbersforthegraph,whichcanbeeasilyaddedtothetable.Listenforstudentswhoare
expressingtheideathatthevaluesontheleftsideofthegrapharejusttheoppositeofthevalueson
therightsideofthegraph.
Asstudentsareworkingonthetransformations,supporttheminconnectingtotheirpreviouswork
withfunctionsandidentifyingthetransformationsfirst,andthenusinganchorpointsfromthe
originalgraphtofindtheirnewgraph.
Discuss:
Beginthediscussionbyhavingastudentpresentatableofvaluesthatshowsthefirst,second,and
thirddifferences.Asktheclasstoexplainhowthedifferencesrelatetoeachother,i.e.aconstant
thirddifferencemeansthattheseconddifferenceislinear,alinearseconddifferencemeansthat
thefirstdifferenceisquadratic.Remindstudentsthat,generally,functionsaredefinedbytheir
ratesofchange,andthepatternsinratesofchangethatweanticipatedin3.1Scott’sMachoMarch
Madnessareconsistentacrosspolynomials.
Movethediscussiontothegraphinproblem#2.Askastudenttosharehowtheyusedthetableto
createthegraphandhowtheycanseetherateofchangeinthegraph.Askstudentstodescribe
whythevaluestotheleftofzeroarenegativeforacubicfunctionandreinforcetheideathatwhen
negativenumbersaresquared,theproductispositiveandwhennegativenumbersarecubed,the
productisnegative.Tellstudentsthattheirtableswillhelpthemwiththeanchorpointstheyneed
totransformthegraphof!(#) = #& .Theyshouldbeabletoeasilyknowthepoints(0,0),(1,1),
(-1,-1),(2,8),and(-2,-8)andusethemforthetransformations.
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Continuethediscussionbyaskingstudentstosharetheirworkonthegraphinquestion#4.Be
surethatstudentsdemonstratehowtheydeterminedthetransformationsandthenusedthe
anchorpointstolocateandgraphthenewfunction.
Finally,discusstheremainingquestions.Question7cmayproducealivelydiscussionsince
studentsoftenbelievethatcubinganumberalwaysmakesitbiggerthansquaringthenumber.
Afterdiscussinghowthisbeliefisnottrueforfractions,projectagraphof!(#) = #&and,(#) = #-
togetherandzoominoneachofthefollowingintervalstoseewhichfunctionisgreaterinthe
interval:(−∞, −1), (−1, 0), (0, 1), (1,∞).
AlignedReady,Set,Go:PolynomialFunctions4.2
ALGEBRA 2// MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
READY Topic:Addingandsubtractingbinomials
Addorsubtractasindicated.
1. (6# + 3) + (4# + 5)
2. (# + 17) + (9# − 13) 3. (7# − 8) + (−2# + 9)
4. (4# + 9) − (# + 2)
5. (−3# − 1) − (2# + 5) 6. (8# + 3) − (−10# −
9)
7. (3# − 7) + (−3# − 7)
8. (−5# + 8) − (−5# +
7)
9. (8# + 9) − (7# + 9)
10. Usethegraphsof0(#)and1(#)tosketchthegraphsof0(#) + 1(#)and0(#)– 1(#).
0(#) + 1(#) 0(#)– 1(#).
READY, SET, GO! Name PeriodDate
9
ALGEBRA 2// MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
SET Topic:Comparingsimplepolynomials
11. Completethetablesbelowfor5 = #7895 = #:7895 = #;
x 5 = #--−1
0
1
x 5 = #:
-1—1
0
1
x 5 = #;
-1—1
0
1
12. Whatassumptionmightyoubetemptedtomakeaboutthegraphsof
5 = #, 5 = #:7895 = #;basedonthevaluesyoufoundinthe3tablesabove?
13. Whatdoyoureallyknowaboutthegraphsof5 = #7895 = #:7895 = #;despitethe
valuesyoufoundinthe3tablesabove?
14.Completethetableswiththeadditionalvalues.
x 5 = #−1
−12Q
0
12Q
1
x 5 = #:−1
−12Q
0
12Q
1
x 5 = #;−1 −1
2Q
0
12Q
1
10
ALGEBRA 2// MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
15.Graph5 = #7895 = #:7895 = #;ontheinterval[−1, 1],usingthesamesetofaxes.
16.Completethetableswiththeadditionalvalues.
x 5 = #−2
−1
−12Q
0
12Q
1
2
x 5 = #:−2
−1
−12Q
0
12Q
1
2
x 5 = #;−2
−1 −1
2Q
0
12Q
1
2
11
ALGEBRA 2// MODULE 4
POLYNOMIAL FUNCTIONS – 4.2
4.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
17.Graph5 = #7895 = #:7895 = #;ontheinterval[-2,2],usingthesamesetofaxes.
GO Topic:UsingtheexponentrulestosimplifyexpressionsSimplify.
18.#T :Q ∙ #TVQ ∙ #
TWQ 19.7X ;Q ∙ 7
:TYQ ∙ 7
XT;Q 20.ZW
[Q ∙ Z:TWQ ∙ Z
;X\Q
12
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.3 Building Strong Roots A Solidify Understanding Task
Whenworkingwithquadraticfunctions,welearned
theFundamentalTheoremofAlgebra:
An"#$degreepolynomialfunctionhas"roots.Inthistask,wewillbeexploringthisideafurtherwithotherpolynomialfunctions.
First,let’sbrushuponwhatwelearnedaboutquadratics.Theequationsandgraphsoffour
differentquadraticequationsaregivenbelow.Findtherootsforeachandidentifywhetherthe
rootsarerealorimaginary.
1.
a)%(') = '* + ' − 6
b)g(') = '* − 2' − 7
Roots: Roots:
Typeofroots: Typeofroots:
c)ℎ(') = '* − 4' + 4
d)2(') = '* − 4' + 5
Roots: Roots:
Typeofroots: Typeofroots:
CC
BY
Rob
Lee
http
s://f
lic.k
r/p/
5p4B
R
13
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
2.Didallofthequadraticfunctionshave2roots,aspredictedbytheFundamentalTheoremof
Algebra?Explain.
3.It’salwaysimportanttokeepwhatyou’vepreviouslylearnedinyourmathematicalbagoftricks
sothatyoucanpullitoutwhenyouneedit.Whatstrategiesdidyouusetofindtherootsofthe
quadraticequations?
4.Usingyourworkfromproblem1,writeeachofthequadraticequationsinfactoredform.When
youfinish,checkyouranswersbygraphing,whenpossible,andmakeanycorrectionsnecessary.
a)%(') = '* + ' − 6
b)g(') = '* − 2' − 7
Factoredform:
Factoredform:
c)ℎ(') = '* − 4' + 4
d)2(') = '* − 4' + 5
Factoredform:
Factoredform:
5.Basedonyourworkinproblem1,wouldyousaythatrootsarethesameas'-intercepts?Explain.
6.Basedonyourworkinproblem4,whatistherelationshipbetweenrootsandfactors?
14
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Nowlet’stakeacloserlookatcubicfunctions.We’veworkedwithtransformationsof
%(') = '4,butwhatwe’veseensofarisjustthetipoftheiceberg.Forinstance,consider:
6(') = '4 − 3'* − 10'
7.Usethegraphtofindtherootsofthecubicfunction.Usetheequationtoverifythatyouare
correct.Showhowyouhaveverifiedeachroot.
8.Write6(')infactoredform.Verifythatthefactoredformisequivalenttothestandardform.
9.Aretheresultsyoufoundin#7consistentwiththeFundamentalTheoremofAlgebra?Explain.
15
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Here’sanotherexampleofacubicfunction.
%(') = '4 + 7'* + 8' − 16
10.Usethegraphtofindtherootsofthecubicfunction.
11.Write%(')infactoredform.Verifythatthefactoredformisequivalenttothestandardform.Makeanycorrectionsneeded.
12.Aretheresultsyoufoundin#10consistentwiththeFundamentalTheoremofAlgebra?
Explain.
13.We’veseenthemostbasiccubicpolynomialfunction,ℎ(') = '4andweknowitsgraphlookslikethis:
Explainhowℎ(') = '4isconsistentwiththeFundamentalTheoremofAlgebra.
16
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
14.Hereisonemorecubicpolynomialfunctionforyourconsideration.Youwillnoticethatitis
giventoyouinfactoredform.Usetheequationandthegraphtofindtherootsof;(').
;(') = (' + 3)('* + 4)
15.Usetheequationtoverifyeachroot.Showyourworkbelow.
16.Aretheresultsyoufoundin#14consistentwiththeFundamentalTheoremofAlgebra?
Explain.
17.Explainhowtofindthefactoredformofapolynomial,giventheroots.
18.Explainhowtofindtherootsofapolynomial,giventhefactoredform.
17
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.3 Building Strong Roots – Teacher Notes A Solidify Understanding Task Purpose:ThepurposeofthistaskistoextendtheFundamentalTheoremofAlgebrafromquadratic
functionstocubicfunctions.Thetaskasksstudentstousegraphsandequationstofindrootsand
factorsandtoconsidertherelationshipbetweenthem.Studentswillalsoconsiderquadraticand
cubicfunctionswithmultiplerealrootsandimaginaryroots.
CoreStandardsFocus:
A.SSE.1Interpretexpressionsthatrepresentaquantityintermsofitscontext.
a.Interpretpartsofanexpression,suchasterms,factors,andcoefficients.
A.APR.3Identifyzerosofpolynomialswhensuitablefactorizationsareavailable,andusethezeros
toconstructaroughgraphofthefunctiondefinedbythepolynomial.
N.CN.9KnowtheFundamentalTheoremofAlgebra;showthatitistrueforquadraticpolynomials.
(ForSecondaryIII,limittopolynomialswithrealcoefficients).
StandardsforMathematicalPractice:
SMP7–Lookforandmakeuseofstructure
Vocabulary:roots,factors,x-intercepts,multiplicity
TheTeachingCycle:
Launch(WholeGroup):
BeginthetaskbyintroducingtheFundamentalTheoremofAlgebra.Studentswereintroducedto
thistheoreminrelationtoquadraticfunctionsinpreviouscourses,sothefirstpartofthistaskisto
activatebackgroundknowledgesothattheirunderstandingandstrategiesforquadraticfunctions
canbeextendedtocubicfunctions.Tellstudentsthattoday’sworkwillinvolvedeterminingthe
numberofrootsforfunctionsaswellastherelationshipbetweenrootsandfactors.Studentsmay
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
needtoberemindedthatrootsarethevaluesof'thatmake%(') = 0.Then,askstudentstowork
onquestions1-6.
Explore(SmallGroup):
Asstudentsareworking,supporttheminusingthegraphstofindroots.Askquestionstohelp
themtomakeconnectionsbetweentheequationsandthegraphs.Listenforstudentswhoareusing
quadraticformulatofindtheexactrootswhentheyarenotobviousonthegraph.Somestudents
maytrytoestimatetheroots;nudgethemtothinkaboutwhattheycoulddotofindexactvalues.In
thecasewheretherootsarenotevidentfromthegraph,askstudentshowtheycouldusethe
equationtofindroots.Whenstudentsareworkingonfindingfactorsfromroots,youmayneedto
remindthemofhowtheysolvedequationsinfactoredform,sothattheythinkabouthowtowork
backwards.
Discuss(WholeGroup):
Beginthediscussionwiththefunctionin#1b.Askapreviously-selectedstudenttosharetheir
workinfindingtheexactvaluesoftherootsusingquadraticformula.Askstudentstofindthe
approximatevaluesandaskwherethosevaluescanbeseenonthegraph.Askanotherstudentto
showhowtheywrotethefactorsfortherootsin#1b.
Next,askastudenttosharehowtheyfoundtherootsfor#1candwroteitinfactoredform
(question2c).AsktheclassifthisfunctionhasthenumberofrootspredictedbytheFundamental
TheoremofAlgebra.Thismaygeneratesomecontroversy.Afterallowingstudentstoshare
arguments,tellthemthatthefactorizationhelpsustoseethatthisfunctionhasamultipleroot.
Explainthatitissaidthatthisisa“rootwithmultiplicityof2”.Remindstudentsthatforquadratics
withmultipleroots,thevertexisgenerallyonthe'-axis.
Haveastudentsharetheirworkfindingtherootsandfactorsforquestion2d.Thiswillserveasa
briefreminderofimaginarynumbers,whichwillbeusedinthistaskandupcomingtasks.
Discussquestions5and6.Manystudentsmayarguethatrootsand'-interceptsarethesame
thing.Ifso,askstudentsiftherootswere'-interceptsinquestion2d.Explainthatarootisdefined
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
asthevalueof'thatmakes%(') = 0.An'-interceptisdefinedtobethepointwhereagraph
crossesthe'-axis.Ifafunctionhasimaginaryroots,itwillnotcrossthe'-axisattheroots,sothe
rootsarenot'-intercepts.Conventionally,arootiswrittenas' = \,and'-interceptsarewritten
aspoints,e.g.(\, 0).Remindstudentsoftherelationshipbetweenrootsandfactors,thenaskthem
toworkontheremainderofthetask.
Explore(SmallGroups):
Supportstudentsastheyareworkingtoapplysomeofthetechniquesthattheylearnedwith
quadraticfunctionstocubicfunctions.Theyshouldstartwithlookingforrootsthatcanbeeasily
identifiedfromthegraphorafactor,andthenusetheremainingfactortofindtheroots.As
studentsareworkingonquestions10and11,lookforastudentthatinitiallythoughtthat(' + 4)is
asingleroot,andthendiscoveredthatitmustbeamultipleroottomaketheequationcubic.Also
lookforastudentthathasfoundtheimaginaryrootsin#14.
Discuss(WholeGroup):
Starttheseconddiscussionwithquestions#10and#11.Haveastudentselectedduringthe
Exploretimesharehis/herworkinfindingtherootsandhowtheydeterminedthat(' + 4)mustbe
amultipleroot.Asktheclasstocomparehowthecubicgraphlookswhenthereisamultipleroot
andhowthequadraticgraphlookedwiththemultipleroot.Thiswillhelpstudentstorecognize
thatwhenapolynomialtouchesthex-axiswithoutcrossingthrough,itprobablycontainsamultiple
rootofevenmultiplicityatthatpoint.
Askstudentstorespondto#13.Theremaybesomedisagreementaboutthisquestion.Again,have
studentsshareideasandcometotheconclusionthatitmusthaveamultiplerootat' = 0.Point
outthatthegraphcrossesthex-axisatthismultipleroot,whichmakesithardertoidentifyasa
multiplerootthanwhenthegraphtouchestheaxisandbouncesoff,asitdoeswithanevennumber
ofmultipleroots.
Askpreviously-selectedstudentstosharetheirworkon#14and#15thatdemonstratesone
methodforsolvingaquadratictofindimaginaryroots.Pointoutthattherearetwoimaginary
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
rootsandaskifthatwouldalwayshappen.Studentsmayrecognizethatusingthequadratic
formulaorsquare-rootingbothsidesoftheequationwouldalwaysleadtotwoimaginaryrootsin
similarcases.
Wrapthediscussionupwiththelasttwoquestions(17and18),demonstratinghowtousethe
rootstogetfactorsandhowtousefactoredformofapolynomialtofindroots.
AlignedReady,Set,Go:PolynomialFunctions4.3
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
READY Topic:Practicinglongdivisiononpolynomials
Divideusinglongdivision.(Theseproblemshavenoremainders.Ifyougetone,tryagain.)1. 2.
3.
4.
SET Topic:ApplyingtheFundamentalTheoremofAlgebra
Predictthenumberofrootsforeachofthegivenpolynomialequations.(RememberthattheFundamentalTheoremofAlgebrastates:Annthdegreepolynomialfunctionhasnroots.)5.!(#) = #& + 3# − 10 6.,(#) = #- + #& − 9# − 9 7./(#) = −2# − 48.2(#) = #3 − #- − 4#& + 4# 9.4(#) = −#& + 6# − 9 10.6(#) = #7 − 5#3 + 4#&
x + 3( ) 5x3 + 2x2 − 45x −18 x − 6( ) x3 − x2 − 44x + 84
x + 2( ) x4 + 6x3 + 7x2 − 6x − 8
READY, SET, GO! Name PeriodDate
x −5( ) 3x3 −15x2 +12x −60
18
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
Belowarethegraphsofthepolynomialsfromthepreviouspage.Checkyourpredictions.Thenusethegraphtohelpyouwritethepolynomialinfactoredform.11.!(#) = #& + 3# − 10Factoredform:
12.,(#) = #- + #& − 9# − 9Factoredform:
13./(#) = −2# − 4Factoredform:
14.2(#) = #3 − #- − 4#& + 4#Factoredform:
19
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.3
4.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
15.4(#) = −#& + 6# − 9Factoredform:
16.6(#) = #7 − 5#3 + 4#&Factoredform:
17.Thegraphsof#15and#16don’tseemtofollowtheFundamentalTheoremofAlgebra,but
thereissomethingsimilarabouteachofthegraphs.Explainwhatishappeningatthepoint(3,0)in#15andatthepoint(0,0)in#16.
GO Topic:SolvingquadraticequationsFindthezerosforeachequationusingthequadraticformula.18.4(#) = #& + 20# + 51
19.4(#) = #& + 10# + 25 20.4(#) = 3#& + 12#
21.4(#) = #& − 11
22.4(#) = #& + # − 1 23.4(#) = #& + 2# + 3
20
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.4 Getting to the Root of the Problem A Solidify Understanding Task
In4.3BuildingStrongRoots,welearnedtopredictthenumberofrootsofapolynomialusingtheFundamentalTheoremofAlgebraandtherelationshipbetweenrootsandfactors.Inthistask,wewillbeworkingonhowtofindalltherootsofapolynomialgiveninstandardform.Let’sstartbythinkingagainaboutnumbersandfactors.1.Ifyouknowthat7isafactorof147,whatwouldyoudotofindtheprimefactorizationof147?Explainyouranswerandshowyourprocesshere:2.Howisyouranswerlikeapolynomialwrittenintheform:!(#) = (# − 7)((# − 3)?Theprocessforfindingfactorsofpolynomialsisexactlyliketheprocessforfindingfactorsofnumbers.Westartbydividingbyafactorweknowandkeepdividinguntilwehaveallthefactors.Whenwegetthepolynomialbrokendowntoaquadratic,sometimeswecanfactoritbyinspection,andsometimeswecanuseourotherquadratictoolslikethequadraticformula.Let’stryit!Foreachofthefollowingfunctions,youhavebeengivenonefactor.Usethatfactortofindtheremainingfactors,therootsofthefunction,andwritethefunctioninfactoredform.3.Function:5(#) = #6 + 3#( − 4# − 12 Factor:(# + 3) Rootsoffunction:Factoredform:
CC
BY
Ber
gen
Smile
snj
http
s://f
lic.k
r/p/
Wrn
PtZ
21
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.Function:5(#) = #6 + 6#( + 11# + 6 Factor:(# + 1) Rootsoffunction:Factoredform:5.Function:5(#) = #6 − 5#( − 3# + 15 Factor:(# − 5) Rootsoffunction:Factoredform:6.Function:5(#) = #6 + 3#( − 12# − 18 Factor:(# − 3) Rootsoffunction:Factoredform: 7.Function:5(#) = #F − 16 Factor:(# − 2) Rootsoffunction:
Factoredform:
22
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
8.Function:5(#) = #6 − #( + 4# − 4 Factor:(# − 2G) Rootsoffunction:Factoredform:9.Isitpossibleforapolynomialwithrealcoefficientstohaveonlyoneimaginaryroot?Explain.10.BasedontheFundamentalTheoremofAlgebraandthepolynomialsthatyouhaveseen,makeatablethatshowsallthenumberofrootsandthepossiblecombinationsofrealandimaginaryrootsforlinear,quadratic,cubic,andquarticpolynomials.
23
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.4 Getting To The Root Of The Problem – Teacher Notes A Solidify Understanding Task Purpose:
Thepurposeofthistaskisforstudentstofindrootsofpolynomialsandwritethepolynomialsin
factoredform.Thistaskbuildsonpreviousalgebraicwork,includingfactoring,polynomiallong
division,andquadraticformula.StudentsalsousetheirknowledgeoftheFundamentalTheoremof
Algebratoknowhowmanyrootsafunctionhasandtoconsiderthepossiblecombinationsofreal
andimaginaryrootsforpolynomialsofdegree1-4.Studentslearnthatimaginaryrootsoccurin
conjugatepairsandusethisknowledgetobothfindrootsandknowthepossiblecombinationsof
rootsforpolynomials.
CoreStandardsFocus:
A.APR.3:Identifyzerospolynomialswhensuitablefactorizationsareavailable,andusethezerosto
constructaroughgraphofthefunctiondefinedbythepolynomial.
N.CN.8:Extendpolynomialidentitiestothecomplexnumbers.Forexample,rewrite#( + 4\](# + 2G)(# − 2G).
N.CN.9:KnowtheFundamentalTheoremofAlgebra;showthatitistrueforquadraticpolynomials.
(InSecondaryIII,limittopolynomialswithrealcoefficients).
StandardsforMathematicalPractice:
SMP1–Makesenseofproblemsandpersevereinsolvingthem
SMP8–Lookforexpressregularityinrepeatedreasoning
Vocabulary:conjugatepairs
TheTeachingCycle:
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Launch:
Beginthetaskbyaskingstudentsaboutquestion1,whatistheprimefactorizationof147andhow
didyoufindit?Studentswilldescribeaprocessofdividingbytheknownfactorandthenbreaking
itdownuntilallthefactorsareprime.Thisisanalogoustotheworkthatwillbedoneinthistask.
We’llbegivenapolynomialandaknownfactor.We’lldividebytheknownfactorandthenbreak
downtheresultuntilallthefactorsarelinear.Question2illustratesthatbothpolynomialsand
numberscanbewritteninfactoredformorstandardform.Tellstudentsthattheywillneedtouse
everythingtheyknowaboutpolynomialsandallthetoolsintheirtoolkit,likequadraticformula,to
breakdownthepolynomialsandfindtheirrootsandfactors.
Explore:
Asstudentsbeginworkingonproblems#3and#4,youmayencountersomestudentswhohave
graphedthefunctionandseenthattheybothhaveintegerrootsthatareeasilyidentifiedfromthe
graph.Ifso,askthemtoverifytheroots,eitherbylongdivisionorsubstitutionintothefunction.If
thisoccurs,youmaywishtoaskoneofthesestudentstopresenttheirworktotheclass,since
connectingthegraphtotherootsisaveryusefulstrategy.
Supportstudentsastheyareworkingtousefactoring,quadraticformula,takingthesquarerootof
bothsides,etc.tosolvetheequationsandfindtheroots.Lookforstudentsthathaveselected
efficientstrategies,ratherthanjustoneconsistentstrategy,toshare.Studentsshouldbeexposedto
theideathatthequadraticformulaisapowerfultool,butnotalwaysthemostefficienttool.
Studentsarelikelytohavesometroublewith#8.Theycantrytouselongdivision,althoughitis
algebraicallymorecomplicatedthanwhattheyhaveseenpreviously.Theymaynotnoticethatthe
givenfactoristhesameasoneofthefactorsin#7,andtheymayormaynothavenoticedthat
imaginaryrootsoccurinpairs.Thisproblemisdesignedtomotivatethediscussionaboutthisidea.
Letstudentsworkontheproblem,butoncetheystartbecomingfrustrated,tellthemtomoveon
andfinishthetask.Ifyouhaveastudentthatisabletosolve#8,he/sheshouldbeaskedtoshare
duringtheclassdiscussion.
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Discuss:
Beginthediscussionwithquestion3.Askastudenttosharethathasusedlongdivisiontodivideby
thegivenfactor(# + 3)andthenfactoredthequadraticthatislefttogettheremainingfactors.Ifa
studentinitiallygraphedthefunctionandthenverifiedtheroots,asdiscussedintheExplore
narrative,thenaskthemtoshare.Comparethetwoapproachesanddiscusshowagraphcan
supportthealgebraicwork.Remindstudentsthatiftheyuseagraphtofindroots,theymustverify
themalgebraically.
Next,discussquestion5.Askapreviously-selectedstudenttosharethathasdividedbythegiven
factorandthensetthequadraticthatisleftequaltozeroandsolvedbysquarerootingbothsidesof
theequation.Itisacommonerrortoforgettouseboththepositiveandnegativeroots.Ifthishas
happenedinclass,remindstudentsthatthiserrorwillcausethemtomissoneoftheroots
predictedbytheFundamentalTheoremofAlgebra.
Discuss#6.Thepresentingstudentshouldhaveusedthequadraticformulatosolvethepolynomial
thatremainedafterdividingbythegivenfactor.Thisproblemprovidestheopportunityto
reinforcehowtosimplifyexpressionsthatresultfromthequadraticformula.
Brieflydiscussquestion7.Ifpossible,haveastudentthathasfactoredtheinitialpolynomialshare
theirworktodemonstratethatthereismorethanonewaytosolvethesetypesofproblems.Be
surethatstudentsnoticethatproblem#6producedapairofimaginaryrootsusingthequadratic
formula,andproblem7producedapairofimaginaryrootsbysquarerootingbothsidesofthe
equation.Tellstudentsthesearecalledconjugatepairs.
Movetoquestion8.Ifyourclassroomclimateallowsstudentstofeelcomfortablesharingwork
thatisn’tentirelysuccessful,youmaywanttohaveastudentsharetheirattemptatlongdivision.
Askstudentsifwhattheyhavenoticedaboutcomplexrootsinpreviousproblemsmaybeusefulin
thisproblem.UsethegraphofthefunctionandtheFundamentalTheoremofAlgebratoarguethat
theremustbeanotherimaginaryroot.Thenshowstudentshowtousetheconjugateofthegiven
roottofindtheremainingroots.Verifyyourworkfortheclassbygraphingboththestandardform
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
andthefactoredformtoshowtheyareequivalent.Makeexplicittostudentsthatimaginaryroots
occurinconjugatepairs.
Finally,wrapupthediscussionbycompletingthetableforquestion10,showingthepossible
combinationsofrealandimaginaryrootsforeachofthefunctiontypes.
AlignedReady,Set,Go:PolynomialFunctions4.4
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.4
4.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
READY Topic:Orderingnumbersfromleasttogreatest
Orderthenumbersfromleasttogreatest.1.100$ √100 &'()100 100 2+,
2.2-+ −√100 &'() /181 0 (−2)+
3.2, √25 &'()8 2(5,), 5 ≠ 0 (2)-89
4.&'($3$ &'(;5-) &'(<6, &'(>4-+ &'()2$
Refertothegivengraphtoanswerthequestions.Insert>,<, 'B =ineachstatementtomakeittrue.
5.D(0)__________((0)6.D(2)__________((2)7.D(−1)__________((−1)8.D(1)__________((−1)
9.D(5)__________((5)
10.D(−2)__________((−2)
READY, SET, GO! Name PeriodDate
D(5)
((5)
24
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.4
4.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
SET Topic:FindingtherootsandfactorsofapolynomialUsethegivenroottofindtheremainingroots.Thenwritethefunctioninfactoredform.
Function Roots Factoredform11.D(5) = 5$ − 135) + 525 − 60 5 = 5
12.((5) = 5$ + 65) − 115 − 66 5 = −6
13.G(5) = 5$ + 175) + 925 + 150 5 = −3
14.J(5) = 5> − 65$ + 35) + 125 − 10 5 = √2
25
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.4
4.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
GO Topic:Usingthedistributivepropertytomultiplycomplexexpressions
Multiplyusingthedistributiveproperty.Simplify.Writeanswersinstandardform.15.K5 − √13LK5 + √13L 16.K5 − 3√2LK5 + 3√2L
17.(5 − 4 + 2M)(5 − 4 − 2M) 18.(5 + 5 + 3M)(5 + 5 − 3M)
19.(5 − 1 + M)(5 − 1 − M) 20.K5 + 10 − √2MLK5 + 10 + √2ML
26
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.5 Is This The End?
A Solidify Understanding Task
Inpreviousmathematicscourses,youhavecomparedand
analyzedgrowthratesofpolynomial(mostlylinearand
quadratic)andexponentialfunctions.Inthistask,weare
goingtoanalyzeratesofchangeandendbehaviorby
comparingvariousexpressions.
PartI:Seeingpatternsinendbehavior
1.Inasmanywaysaspossible,compareandcontrastlinear,quadratic,cubic,andexponentialfunctions.2.Usingthegraphprovided,writethefollowingfunctionsvertically,fromgreatesttoleastfor@ = B.Putthefunctionwiththegreatestvalueontopandthefunctionwiththesmallestvalueon
thebottom.Putfunctionswiththesamevaluesatthesamelevel.Anexample,E(F) = FG,hasbeen
placedonthegraphtogetyoustarted.
H(F) = 2J K(F) = FL + FN − 4 Q(F) = FN − 20
ℎ(F) = FT − 4FN + 1 V(F) = F + 30 X(F) = FY − 1
Z(F) = FT [(F) = \]
N^J _(F) = F`
3.WhatdeterminesthevalueofapolynomialfunctionatF = 0?Isthistrueforothertypesof
functions?
4.WritethesameexpressionsonthegraphinorderfromgreatesttoleastwhenFrepresentsa
verylargenumber(thisnumberissolarge,sowesaythatitisapproachingpositiveinfinity).Ifthe
valueofthefunctionispositive,putthefunctioninquadrant1.Ifthevalueofthefunctionis
negative,putthefunctioninquadrantIV.Anexamplehasbeenplacedforyou.
CC
BY
Cai
tlin
H
http
s://f
lic.k
r/p/
6S4X
qn
27
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
5.WhatdeterminestheendbehaviorofapolynomialfunctionforverylargevaluesofF?
6.WritethesamefunctionsinorderfromgreatesttoleastwhenFrepresentsanumberthatis
approachingnegativeinfinity.Ifthevalueofthefunctionispositive,placeitinQuadrantII,ifthe
valueofthefunctionisnegative,placeitinQuadrantIII.Anexampleisshownonthegraph.
7.WhatpatternsdoyouseeinthepolynomialfunctionsforFvaluesapproachingnegativeinfinity?
Whatpatternsdoyouseeforexponentialfunctions?Usegraphingtechnologytotestthesepatterns
withafewmoreexamplesofyourchoice.
8.Howwouldtheendbehaviorofthepolynomialfunctionschangeiftheleadtermswerechanged
frompositivetonegative?
28
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
@ = B @ → ∞ @ → −∞
E(F) = FG
K(F) = FG m = FN
m = FL
29
SECONDARY MATH III // MODULE 3
POLYNOMIAL FUNCTIONS– 3.9
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
FT
FN − 20
F + 30 FY − 1
2J
é1
2èJ
FG F`
FL + FN − 4 FT − 4FN + 1
35
SECONDARY MATH III // MODULE 3
POLYNOMIAL FUNCTIONS– 3.9
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.5 Is This The End? – Teacher Notes A Solidify Understanding Task
Purpose:Thepurposeofthistaskistosolidifystudentunderstandingofhowthedegreeofthepolynomialfunctionimpactstherateofchangeandendbehavior.Bycomparingthevaluesof
expressionswith‘extreme’values,studentswillbeableto:• Understandthatthedegreeofthepolynomialisthehighestvaluedwholenumberexponent
andthatthistermdeterminestheendbehavior(regardlessoftheothertermsinthe
expression).
• Determinethatthehigherthedegreeofapolynomial,thegreaterthevalueasFapproaches
infinity.Understandthatwhilethehighestdegreepolynomialhasthegreatestvalueas
F → ∞,thatexponentialfunctionshavethegreatestrateofchange,andthereforethe
greatestvaluewhenFbecomesverylarge.
• Identifydifferencesbetweenevenandodddegreefunctions.Inthistask,studentswillknow
theendbehaviorforodddegreefunctions(asF →−∞, H(F) → −∞andthatbotheven
andodddegreepolynomialfunctionsasF → ∞, H(F) → ∞)aslongastheco-efficientis
positiveandrealizethattheoppositeistrueiftheco-efficientisnegative.
TeacherNote:Makecopiesoftheexpressionsandhavethemcutoutinadvance.Tomakethemost
ofthewholegroupdiscussion,bepreparedbyhavingseveral‘movablecopies’ofeachexpression
(largecutoutsareattachedandbeingabletomoveexpressionsonaSmartboardorusinga
documentcamerawillbehandy).Youwillwantmorethanonesetsothateveryonecanvisuallysee
thechangeinorderdependingonthevalueschosenforF.SeeDiscusssectionformoredetails.
CoreStandardsFocus:
F.LE.3Observeusinggraphsandtablesthataquantityincreasingexponentiallyeventuallyexceedsaquantityincreasinglinearly,quadratically,or(moregenerally)asapolynomialfunction.
A.SSE.1Interpretexpressionsthatrepresentaquantityintermsofitscontext.
SECONDARY MATH III // MODULE 3
POLYNOMIAL FUNCTIONS– 3.9
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
a.Interpretpartsofanexpression,suchasterms,factors,andcoefficients.F.IF.4Forafunctionthatmodelsarelationshipbetweentwoquantities,interpretkeyfeaturesofgraphsandtablesintermsofthequantities,andsketchgraphsshowingkeyfeaturesgivenaverbaldescriptionoftherelationship.Keyfeaturesinclude:intercepts;intervalswherethefunctionisincreasing,decreasing,positive,ornegative;relativemaximumsandminimums;symmetries;end
behavior;andperiodicity.
F.BF.3Identifytheeffectonthegraphofreplacingf(x)byf(x)+k,kf(x),f(kx),andf(x+k)forspecificvaluesofk(bothpositiveandnegative);findthevalueofkgiventhegraphs.Experimentwithcasesandillustrateanexplanationoftheeffectsonthegraphusingtechnology.Includerecognizingevenandoddfunctionsfromthegraphsandalgebraicexpressionsforthem.RelatedStandards:F.IF.7StandardsforMathematicalPractice:
SMP1–Makesenseofproblemsandpersevereinsolvingthem
SMP3–Constructviableargumentsandcritiquethereasoningofothers
SMP5–Useappropriatetoolsstrategically
SMP7–Lookforandmakeuseofstructure
Vocabulary:endbehaviorTheTeachingCycle:
Launch(WholeClass):
Beginbyreadingtheintroductioninthetaskandthenexplaintostudentsthatwhiletheywillbe
comparingandorderingexpressions,theyshouldalsopayattentiontowhytheexpressionsareina
particularorder.Tellstudentsthattheyshouldbelookingforpatternsthattheycangeneralizeand
use.
SECONDARY MATH III // MODULE 3
POLYNOMIAL FUNCTIONS– 3.9
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Explore(SmallGroup):
Startthetaskbyhavingstudentsworkindividuallyandthenworktogetherinsmallgroupsonthe
restofthetask.Asyoumonitor,listenforstudentreasoningthroughout,payingparticularattention
whentheyarediscussingtheorderoftheexpressionsinquestions3and4(connectingtoend
behavior).Takenoteofhowdifferentgroupsaredeterminingorder.Aretheyplugginginvalues?
Aretheylookingatagraphicalrepresentation?Aretheymakingassumptionsbasedontheir
knowledgeofexponents?Asstudentsanswerquestion5,pressforthemtoexplaintheirreasoning.
Listenforanswersthatincludecomparingpolynomialstoexponentialfunctions(andthat
exponentialfunctionswithabasegreaterthanonewillalwaysoutgrowanypolynomialfunction).
Alsolistenforanswersthatdistinguishbetweenwhenthedegreeofthepolynomialisevenversus
whenitisodd(andhowthisimpactsthevaluesasF →−∞).
Discuss(WholeClass):
Whenallstudentshavehadtheopportunitytoanswerquestion6(somemayhavealready
completedallquestions),movetothewholegroupdiscussion.Beginwithastudentthatshares
theirorderingforquestion2.Askthestudenttoexplainhowtheyfiguredouttheorder.During
thisexplanation,thereshouldbesomediscussionofsubstitutingin0forxandfindingthattheonly
termleftinapolynomialistheconstantterm.Asktheclassifthiswillbethecaseforevery
polynomialfunction.Asktheclassifthisistrueofallfunctions.Theyshouldrecognizethatsome
functions,likelogarithmsareundefinedatF = 0,andsomefunctions,likeexponentials,dependon
morethanjustaconstantterm.
Next,askastudenttosharetheirorderingofthefunctionsfor#4.Useeithertheaxesprovidedin
thetaskorpostalargersetofaxesandusethelargefunctioncards,thatareprovidedfollowingthe
teachernotes,sothattheorderisveryvisualforstudents.Focusfirstontheorderofthe
polynomialfunctions.Besurethatstudentsnoticethatthehighest-poweredtermessentially
determinestheendbehaviorforlargevaluesofx.Lookspecificallyath(x)andr(x).Sincethese
twofunctionsarebothdegree5polynomials,thentheyaremoredifficulttoorder.Askforstudents
tosharedifferentideasforhowtocomparethesetwofunctions,includingusingtechnologyto
graphbothfunctionsandcomparingthemforlargevalues,substitutinglargenumbersintoboth
SECONDARY MATH III // MODULE 3
POLYNOMIAL FUNCTIONS– 3.9
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
functionsandcomparing,andreasoningabouttheeffectoftheadditionaltermsinh(x).Itislikely
thattherewillbesomecontroversyaroundwhetherornottheexponentialfunctionisthegreatest
asF → ∞.Lookforsimilarstrategiestocomparetheexponentialwiththehighest-powered
polynomial.Then,askstudentstoconsidertheratesofchangeofthetwofunctionstothinkabout
whichoneisthegreatestforlargevaluesofx.Havestudentscalculatetheaveragerateofchangeof
bothfunctionsfrom[15,20]toseethattherapidrateofchangeoftheexponentialfunctionwill
eventuallymakeitexceedanypolynomial.
Next,askastudenttosharetheirorderingofthefunctionsforquestion#6.Again,makethevisual
availablesothatallstudentscaneasilyseethepatternthateven-poweredpolynomialsapproach
infinityasF → −∞andodd-poweredpolynomialsapproachnegativeinfinityasF → −∞.Ask
studentsifthisisconsistentwiththeirexperienceofquadraticandcubicfunctions,andwhyit
wouldbeso.Askhowthisconnectstothenumberandtypesofrootsthatwerefoundfor
polynomialfunctionsintheprevioustask.(Bepreparedtopullthechartoutaspartofthe
discussion.)Alsodiscussquestion#8andtheeffectofchangingthesignoftheleadcoefficientina
polynomial.
AskstudentstoshareasmanyoftheproblemsinPartIIastimeallows.Besurethattheyareusing
theresultsofPartIandthecorrectnotationtorecordtheirresults.
Finallyaskstudentsfortheirobservationsaboutevenfunctions.Highlightobservationsthat
includetheideathatthegraphsaresymmetricaboutthey-axis.Askstudentshowthedefinition
givenrelatestothesymmetryofthegraphsandhelpthemtoarticulatethattheoutputofthe
functionisthesameforbothpositiveandnegativevaluesofFinevenfunctions.Thisistrueofthe
parentfunctionforalleven-degreepolynomialsandiftheyhaveaverticaltranslationand/ora
verticalstretch.
Repeattheprocessbyaskingstudentsfortheirobservationsaboutoddfunctions.Itmaybeharder
torecognizethe180˚rotationabouttheorigin.Demonstratingthisideawithapieceofpattypaper
mayhelpstudentstoseeitmoreeasily.Reinforcehowthedefinitionofanoddfunctioncreatesthis
SECONDARY MATH III // MODULE 3
POLYNOMIAL FUNCTIONS– 3.9
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
patterninthegraphofoddfunctions.Askstudentshowtotellifanodd-degreepolynomialwillbe
anoddfunction.Supportthemtothinkaboutwhichtransformationsofanodd-degreeparent
functionlikeH(F) = FLwillresultinanoddfunction.Closethediscussionbyaskingstudentsto
shareacoupleofexamplesoffunctionsthatareneitheroddnoreven.Manyoftheexamplesfrom
earlierinthetaskcanbeusedforthispurpose.
AlignedReady,Set,Go:PolynomialFunctions4.5
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.5
Needhelp?Visitwww.rsgsupport.org
READY Topic:Recognizingspecialproducts
Multiply.1.(" + 5)(" + 5) 2.(" − 3)(" − 3) 3.(( + ))(( + ))
4.Inproblems1–3theanswersarecalledperfectsquaretrinomials.Whatabouttheseanswersmakesthembeaperfectsquaretrinomial?
5.(" + 8)(" − 8) 6.+" + √3-+" − √3- 7.(" + ))(" − ))
8.Theproductsinproblems5–7endupbeingbinomials,andtheyarecalledthedifferenceoftwosquares.Whatabouttheseanswersmakesthembethedifferenceoftwosquares?
Whydon’ttheyhaveamiddletermliketheproblemsin1–3?9.(" − 3)(". + 3" + 9) 10.(" + 10)(". − 10" + 100) 11.(( + ))((. − () + ).)
12.Theworkinproblems9–11makesthemfeelliketheanswersaregoingtohavealotofterms.Whathappensintheworkoftheproblemthatmakestheanswersbebinomials?
Theseanswersarecalledthedifferenceoftwocubes(#9)andthesumoftwocubes(#10
and#11.)Whatabouttheseanswersmakesthembethesumordifferenceoftwocubes?
READY, SET, GO! Name PeriodDate
30
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.5
Needhelp?Visitwww.rsgsupport.org
SET Topic:Determiningvaluesofpolynomialsatzeroandat±∞.(Endbehavior)
Statethey-intercept,thedegree,andtheendbehaviorforeachofthegivenpolynomials.13.5(") = "7 + 7"9 − 9": + ". − 13" + 8y-intercept:Degree:Endbehavior:As" → −∞, 5(") → __________As" → +∞, 5(") → __________
14.?(") = 3"9 + ": + 5". − " − 15y-intercept:Degree:Endbehavior:As" → −∞, ?(") → __________As" → +∞, ?(") → __________
15.ℎ(") = −7"A + ".y-intercept:Degree:Endbehavior:As" → −∞, ℎ(") → __________As" → +∞, ℎ(") → __________
16.B(") = 5". − 18" + 4y-intercept:Degree:Endbehavior:As" → −∞, B(") → __________As" → +∞, B(") → __________
17.D(") = ": − 94". − " − 20y-intercept:Degree:Endbehavior:As" → −∞, D(") → __________As" → +∞, D(") → __________
18.F = −4" + 12y-intercept:Degree:Endbehavior:As" → −∞, F → __________As" → +∞, F → __________
31
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.5
Needhelp?Visitwww.rsgsupport.org
Topic:Identifyingevenandoddfunctions19.Identifyeachfunctionaseven,odd,orneither.a)5(") = ". − 3
b)5(") = ".
c)5(") = (" + 1).
d)5(") = ":
e)5(") = ": + 2
f)5(") = (" − 2):
GO Topic:Factoringspecialproducts
Fillintheblanksonthesentencesbelow.20.TheexpressionGH + HGI+ IHiscalledaperfectsquaretrinomial.Icanrecognizeitbecause
thefirstandlasttermswillalwaysbeperfect___________________________________________.
Themiddletermwillbe2timesthe______________________________and_______________________________.
Therewillalwaysbea__________________signbeforethelastterm.
Itfactorsas(__________________)(__________________).
32
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.5
Needhelp?Visitwww.rsgsupport.org
21.TheexpressionGH − IHiscalledthedifferenceof2squares.Icanrecognizeitbecauseit’sa
binomialandthefirstandlasttermsareperfect_________________________________________________.
Thesignbetweenthefirsttermandthelasttermisalwaysa______________________________.
Itfactorsas(__________________)(__________________).
22.TheexpressionGJ + IJiscalledthesumof2cubes.Icanrecognizeitbecauseit’sabinomial
andthefirstandlasttermsare_____________________________________.Theexpression(: + ):factors
intoabinomialandatrinomial.Icanrememberitasashort(______)andalong(________________).
Thesignbetweenthetermsinthebinomialisthe_____________________asthesigninthe
expression.Thefirstsigninthetrinomialisthe_________________________ofthesigninthe
binomial.That’swhyallofthemiddletermscancelwhenmultiplying.
Thelastsigninthetrinomialisalways____________.
Itfactorsas(__________________)(___________________________________).
Factorusingwhatyouknowaboutspecialproducts.23.25". + 30 + 9
24.". − 16 25.": + 27
26.49". − 36 27.": − 1
28.64". − 240 + 225
33
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
PartII:Usingendbehaviorpatterns
Foreachsituation:
• Determinethefunctiontype.Ifitisapolynomial,statethedegreeofthepolynomialand
whetheritisanevendegreepolynomialoranodddegreepolynomial.
• Describetheendbehaviorbasedonyourknowledgeofthefunction.Usetheformat:
AsF → −∞, H(F) → ______r[srtF → ∞H(F) → ______
1. H(F) = 3 + 2F
Functiontype:
Endbehavior:AsF → −∞, H(F) → ______
Endbehavior:AsF → ∞, H(F) → ______
2.H(F) = FY− 16
Functiontype:
Endbehavior:AsF → −∞, H(F) → ______
Endbehavior:AsF → ∞, H(F) → ______
3.H(F) = 3J
Functiontype:
Endbehavior:AsF →−∞, H(F) → ______
Endbehavior:AsF → ∞, H(F) → ______
4.H(F) = FL+ 2F
N− F + 5
Functiontype:
Endbehavior:AsF → −∞, H(F) → ______
Endbehavior:AsF → ∞, H(F) → ______
5.H(F) = −2FL+ 2F
N− F + 5
Functiontype:
Endbehavior:AsF →−∞, H(F) → ______
Endbehavior:AsF → ∞, H(F) → ______
6.H(F) = EvQNF
Functiontype:
Endbehavior:AsF →−∞, H(F) → ______
Endbehavior:AsF → ∞, H(F) → ______
Usethegraphsbelowtodescribetheendbehaviorofeachfunctionbycompletingthe
statements.
7. 8.
Endbehavior:AsF →−∞, H(F) → ______
Endbehavior:AsF → ∞, H(F) → ______
Endbehavior:AsF →−∞, H(F) → ______
Endbehavior:AsF → ∞, H(F) → ______
34
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
9.Howdoestheendbehaviorforquadraticfunctionsconnectwiththenumberandtypeof
rootsforthesefunctions?Howdoestheendbehaviorforcubicfunctionsconnectwiththe
numberandtypeofrootsforcubicfunctions?
PartIII:EvenandOddFunctions
Somefunctionsthatarenotpolynomialsmaybecategorizedasevenfunctionsoroddfunctions.
Whenmathematicianssaythatafunctionisanevenfunction,theymeansomethingveryspecific.
1.Let’sseeifyoucanfigureoutwhatthedefinitionofanevenfunctioniswiththeseexamples:
Evenfunction:
H(F) = FN
Notanevenfunction:
Q(F) = 2J
Differences:
Evenfunction:
H(F) = FY− 3
Notanevenfunction:
Q(F) = F(F + 3)(F − 2)
Differences:
35
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Evenfunction:
H(F) = −|F| + 4
Notanevenfunction:
Q(F) = −|F + 4|
Differences:
Evenfunction:
H(2) = 5r[sH(−2) = 5
Notanevenfunction:
Q(2) = 3r[sQ(−2) = 5
Differences:
2.Whatdoyouobserveaboutthecharacteristicsofanevenfunction?
3.Thealgebraicdefinitionofanevenfunctionis:
�(@)isanevenfunctionifandonlyif�(@) = �(−@)forallvaluesof@inthedomainof�.
Whataretheimplicationsofthedefinitionforthegraphofanevenfunction?
4.Arealleven-degreepolynomialsevenfunctions?Useexamplestoexplainyouranswer.
5.Let’strythesameapproachtofigureoutadefinitionforoddfunctions.
36
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Oddfunction:
H(F) = FL
Notanoddfunction:
Q(F) = logN F
Differences:
Oddfunction:
H(F) = −FT
Notanoddfunction:
Q(F) = FL+ 3F − 7
Differences:
Oddfunction:H(F) =]
J
Notanoddfunction:
Q(F) = 2F − 3
Differences:
Oddfunction:
H(2) = 3r[sH(−2) = −3
Notanoddfunction:
Q(2) = 3r[sQ(−2) = 5
Differences:
37
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS– 4.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
6.Whatdoyouobserveaboutthecharacteristicsofanoddfunction?
7.Thealgebraicdefinitionofanoddfunctionis:
�(@)isanoddfunctionifandonlyif�(−@) = −�(@)forallvaluesof@inthedomainof�.
Explainhoweachoftheexamplesofoddfunctionsabovemeetthisdefinition.
8.Howcanyoutellifanodd-degreepolynomialisanoddfunction?
9.Areallfunctionseitheroddoreven?
38
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.6 Puzzling Over Polynomials A Practice Understanding Task
Foreachofthepolynomialpuzzlesbelow,afewpiecesofinformationhavebeengiven.Yourjobistousethosepiecesofinformationtocompletethepuzzle.Occasionally,youmayfindamissingpiecethatyoucanfillinyourself.Forinstance,althoughsomeoftherootsaregiven,youmaydecidethatthereareothersthatyoucanfillin.
1.
Function(infactoredform)Function(instandardform)Endbehavior:!"$ → −∞, )($) → _____!"$ → ∞, )($) → _____Roots(withmultiplicity):-2,1,and1Valueofleadingco-efficient:-2Degree:3
Graph:
CC
BY
Just
in T
aylo
r
http
s://f
lic.k
r/p/
4fU
zTo
39
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
2.Function(infactoredform)Function(instandardform)Endbehavior:!"$ → −∞, )($) → _____!"$ → ∞, )($) → _____Roots(withmultiplicity):
2 + /, 4, 0Valueofleadingco-efficient:1Degree:4
Graph:
3.
Function:)($) = 2($ − 1)($ + 3)5Endbehavior:!"$ → −∞, )($) → _____!"$ → ∞, )($) → _____Roots(withmultiplicity):Valueofleadingco-efficient:Domain:Range:AllRealnumbers
Graph:
40
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.
Function:Endbehavior:!"$ → −∞, )($) → ∞!"$ → ∞, )($) → _____Roots(withmultiplicity):(3,0)m:1;(-1,0)m:2(0,0)m:2Valueofleadingco-efficient:-1Domain:Range:
Graph:
5.
Function:Endbehavior:!"$ → −∞, )($) → _____!"$ → ∞, )($) → _____Roots(withmultiplicity):Valueofleadingco-efficient:1Domain:Range:Other:)(0)=16
Graph:
41
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
6.
Function(instandardform):)($) = $6 − 2$5 − 7$ + 2
Function(infactoredform):Endbehavior:!"$ → −∞, )($) → _____!"$ → ∞, )($) → _____Roots(withmultiplicity):-2Domain:Range:
Graph:
7.
Function(instandardform):)($) = $6 − 2$
Function(infactoredform):Endbehavior:!"$ → −∞, )($) → _____!"$ → ∞, )($) → _____Roots(withmultiplicity):Domain:Range:
Graph:
42
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.6 Puzzling Over Polynomials – Teacher Notes A Practice Understanding Task Purpose:Thepurposeofthistaskistietogetherwhatstudentshavelearnedaboutroots,end
behavior,operations,andgraphsofpolynomials.Eachproblemgivesafewfeaturesofapolynomial
andasksstudentstofindotherfeatures,sometimesincludingthegraphs.Thiswillrequirethemto
knowtheendbehaviorofapolynomial,basedonthedegree,andtofindalltheroots,givensomeof
theroots.Inmostcases,studentsareaskedtowritetheequationofthepolynomialortowritethe
equationinadifferentformthanisgiven.
CoreStandardsFocus:
F-IF.7:Graphfunctionsexpressedsymbolicallyandshowkeyfeaturesofthegraph,byhandin
simplecasesandusingtechnologyformorecomplicatedcases.�
a.Graphlinearandquadraticfunctionsandshowintercepts,maxima,andminima.
c.Graphpolynomialfunctions,identifyingzeroswhensuitablefactorizationsareavailable,and
showingendbehavior.(3.2,
A-APR.3:Identifyzerospolynomialswhensuitablefactorizationsareavailable,andusethezerosto
constructaroughgraphofthefunctiondefinedbythepolynomial.
N-CN.8:Extendpolynomialidentitiestothecomplexnumbers.Forexample,rewrite
$5 + 4!"($ + 2/)($ − 2/).
N-CN.9:KnowtheFundamentalTheoremofAlgebra;showthatitistrueforquadraticpolynomials.
(InSecondaryIII,limittopolynomialswithrealcoefficients).
A-CED:Createequationsthatdescribenumbersorrelationships
2.Createequationsintwoormorevariablestorepresentrelationshipsbetweenquantities;graph
equationsoncoordinateaxeswithlabelsandscales.
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
StandardsforMathematicalPractice:
SMP1–Makesenseofproblemsandpersevereinsolvingthem
SMP6–Attendtoprecision
TheTeachingCycle:
Launch:
Launchthetaskbytellingstudentsthattheyaregivenseveralpolynomialpuzzlesthatwillhelp
themtoconnectalltheworkthattheyhavedoneinthemodulesofar.Ineachpuzzletheyaregiven
someinformationandtheyneedtousethatinformationtofindtheotherinformation.Sometimes
thepuzzlesarelittlesneakybecauseinformationthattheyneedisnotgivendirectly,butifthey
thinkaboutwhattheyknow,theycanfindit.
Explore:
Monitorstudentsastheyworktoseewhichproblemsarecausingdifficultysothattheycanbeused
intheclassdiscussion.Youmayneedtosupportstudentsinsolvingproblem2.Oneimaginary
rootisgiven,andtheywillneedtoknowthattheotherrootistheconjugate.Ifstudentsarestuck,
askquestionstohelpremindthemoftherelationshipbetweenimaginaryrootsofapolynomial.As
studentsworkonproblemslike#5and#6,allowthemtousethegivengraphtofindtheinteger
rootsandthenrequirethemtousethoserootstofindtheremainingirrationalorimaginaryroots
usinglongdivision.
Discuss:
Discussasmanyoftheproblemsastimeallows,withpreviously-selectedstudentssharingtheir
workforeachproblem.Startwiththeproblemsthatweremoredifficultsothatstudentshavea
chancetoseehowtoworkthroughsomeofthedifficulties.Afterastudentpresentstheirwork,ask
therestoftheclasstosummarizetheprocessthatthepresentingstudentusedwiththefollowing
sentenceframe:
Intheproblem,weweregiven_________________________________andsoweknew_____________________.
Thenwewereabletofind________________________________by____________________________________________.
Anexampleofusingthesentenceframewithproblem#2is:
ALGEBRA II // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Intheproblem,weweregiven2realrootsand1imaginaryrootandsoweknewtherewas
anotherimaginaryroot,[ − \.
Thenwewereabletofindtheequationbywritingeachrootasafactorandmultiplyingthem
together.
AlignedReady,Set,Go:PolynomialFunctions4.6
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.6
Needhelp?Visitwww.rsgsupport.org
READY Topic:Reducingrationalnumbersandexpressions
Reducetheexpressionstolowestterms.(Assumenodenominatorequals0.)
1.!"#"$
2.&∙(∙"∙"∙"∙)!∙(∙"∙)∙)
3.*+,$
*+,$ 4.
(".&)("01)(".&)("01)
5.(!"0()(".2)("03)(!"0()
6.(&"033)(!".3*)(&"033)(!"0()
7.(4"0*)(".!)4"(".!)(&"0!)
8.!"(&".*)("03)(#"0()"(&".*)("03)(#"0()
9.Whyisitimportantthattheinstructionssaytoassumethatnodenominatorequals0?
SET Topic:Reviewingfeaturesofpolynomials
Someinformationhasbeengivenforeachpolynomial.Fillinthemissinginformation.
10.
Graph:Function:5(6) = 6!Functioninfactoredform:Endbehavior:As6 → −∞, 5(6) → _______As6 → ∞, 5(6) → ______
Roots(withmultiplicity):
Degree:
Valueofleadingco-efficient:
READY, SET, GO! Name PeriodDate
43
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.6
Needhelp?Visitwww.rsgsupport.org
11.Graph:
Functioninstandardform:
Functioninfactoredform:=(6) = −6(6 − 2)(6 − 4)
Endbehavior:As6 → −∞,=(6) → _______As6 → ∞,=(6) → ______Roots(withmultiplicity):Degree:Valueofleadingco-efficient:
12.Graph:
Functioninstandardform:ℎ(6) = 6! − 26& − 36
Functioninfactoredform:
Endbehavior:As6 → −∞, ℎ(6) → _______As6 → ∞, ℎ(6) → ______Roots(withmultiplicity):Degree:ValueofB(C):
13.Graph:Functioninstandardform:
Functioninfactoredform:Endbehavior:As6 → −∞, 5(6) → _______As6 → ∞, 5(6) → ______
Roots(withmultiplicity):
Degree:
y-intercept:
44
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.6
Needhelp?Visitwww.rsgsupport.org
14.Graph:
Functioninstandardform:
Functioninfactoredform:
Endbehavior:As6 → −∞, E(6) → _______As6 → ∞, E(6) → ______
Roots(withmultiplicity):
Degree:
Valueofleadingcoefficient:
15.Graph:
Functioninstandardform:F(6) = 6! + 26& + 6 + 2
Functioninfactoredform:Endbehavior:As6 → −∞, F(6) → _______As6 → ∞, F(6) → ______
Roots(withmultiplicity):
6 = H
Degree:
y-intercept:
16.Finishthegraphifitis
anevenfunction.
17.Finishthegraphifit
isanoddfunction.
45
ALGEBRA 2 // MODULE 4
POLYNOMIAL FUNCTIONS – 4.6
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
4.6
Needhelp?Visitwww.rsgsupport.org
GO Topic:Writingpolynomialsgiventhezerosandtheleadingcoefficient
Writethepolynomialfunctioninstandardformgiventheleadingcoefficientandthezerosofthefunction.
18.Leadingcoefficient:2; JKKLM:2, √2,−√2
19.Leadingcoefficient:−1; JKKLM:1, 1 + √3, 1 − √3
20.Leadingcoefficient:2; JKKLM:4H, −4H
Fillintheblankstomakeatruestatement.21.If5(P) = 0,thenafactorof5(P)mustbe____________________________________.
22.Therateofchangeinalinearfunctionisalwaysa______________________________________.
23.Therateofchangeofaquadraticfunctionis_______________________________________________.
24.Therateofchangeofacubicfunctionis____________________________________________________.
25.Therateofchangeofapolynomialfunctionofdegreencanbedescribedbyafunctionofdegree
________________________.
46