algebra ii - mathematics vision projectuses tables, graphs, equations, and written descriptions of...
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 �
'VODUJPOT�BOE�5IFJS�*OWFSTFT
ALGEBRA II
An Integrated Approach
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
MODULE 1 - TABLE OF CONTENTS
FUNCTIONS AND THEIR INVERSES
1.1Brutus Bites Back – A Develop Understanding Task Develops the concept of inverse functions in a linear modeling context using tables, graphs, and equations. (F.BF.1, F.BF.4, F.BF.4a) Ready, Set, Go Homework: Functions and Their Inverses 1.1
1.2Flipping Ferraris – A Solidify Understanding Task Extends the concepts of inverse functions in a quadratic modeling context with a focus on domain and range and whether a function is invertible in a given domain. (F.BF.1, F.BF.4, F.BF.4c, F.BF.4d)Ready, Set, Go Homework: Functions and Their Inverses 1.2
1.3Tracking the Tortoise – A Solidify Understanding Task Solidifies the concepts of inverse function in an exponential modeling context and surfaces ideas about logarithms. (F.BF.1, F.BF.4, F.BF.4c, F.BF.4d)Ready, Set, Go Homework: Functions and Their Inverses 1.3
1.4 Pulling a Rabbit Out of a Hat – A Solidify Understanding Task Uses function machines to model functions and their inverses. Focus on finding inverse functions and verifying that two functions are inverses. (F.BF.4, F.BF.4a, F.BF.4b) Ready, Set, Go Homework: Functions and Their Inverses 1.4
1.5 Inverse Universe – A Practice Understanding Task Uses tables, graphs, equations, and written descriptions of functions to match functions and their inverses together and to verify the inverse relationship between two functions. (F.BF.4a, F.BF.4b, F.BF.4c, F.BF.4d)Ready, Set, Go Homework: Functions and Their Inverses 1.5
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
1.1 Brutus Bites Back
A Develop Understanding Task
RememberCarlosandClarita?Acoupleofyearsago,theystartedearningmoneybytakingcareofpetswhiletheirownersareaway.Duetotheiramazingmathematicalanalysisandtheirlovingcareofthecatsanddogsthattheytakein,CarlosandClaritahavemadetheirbusinessverysuccessful.Tokeepthehungrydogsfed,theymustregularlybuyBrutusBites,thefavoritefoodofallthedogs.
CarlosandClaritahavebeensearchingforanewdogfoodsupplierandhaveidentifiedtwopossibilities.TheCanineCateringCompany,locatedintheirtown,sells7poundsoffoodfor$5.
Carlosthoughtabouthowmuchtheywouldpayforagivenamountoffoodanddrewthisgraph:
1. WritetheequationofthefunctionthatCarlosgraphed.
CC B
Y Fr
anco
Van
nini
ht
tps:/
/flic
.kr/
p/m
EcoS
h
1
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Claritathoughtabouthowmuchfoodtheycouldbuyforagivenamountofmoneyanddrewthisgraph:
2.WritetheequationofthefunctionthatClaritagraphed.
3. WriteaquestionthatwouldbemosteasilyansweredbyCarlos’graph.WriteaquestionthatwouldbemosteasilyansweredbyClarita’sgraph.Whatisthedifferencebetweenthetwoquestions?
4. Whatistherelationshipbetweenthetwofunctions?Howdoyouknow?
5.Usefunctionnotationtowritetherelationshipbetweenthefunctions.
2
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Lookingonline,Carlosfoundacompanythatwillsell8poundsofBrutusBitesfor$6plusaflat$5shippingchargeforeachorder.Thecompanyadvertisesthattheywillsellanyamountoffoodatthesamepriceperpound.
6. ModeltherelationshipbetweenthepriceandtheamountoffoodusingCarlos’approach.
7. ModeltherelationshipbetweenthepriceandtheamountoffoodusingClarita’sapproach.
8. Whatistherelationshipbetweenthesetwofunctions?Howdoyouknow?
9. Usefunctionnotationtowritetherelationshipbetweenthefunctions.
10. WhichcompanyshouldClaritaandCarlosbuytheirBrutusBitesfrom?Why?
3
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.1 1.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
READYTopic:Inverseoperations
Inverseoperations“undo”eachother.Forinstance,additionandsubtractionareinverseoperations.
Soaremultiplicationanddivision.Inmathematics,itisoftenconvenienttoundoseveraloperations
inordertosolveforavariable.
Solveforxinthefollowingproblems.Thencompletethestatementbyidentifyingthe
operationyouusedto“undo”theequation.
1.24=3x Undomultiplicationby3by_______________________________________________
2. Undodivisionby5by______________________________________________________
3. Undoadd17by_____________________________________________________________
4. Undothesquarerootby___________________________________________________
5. Undothecuberootby_____________________________then___________________
6. Undoraisingxtothe4thpowerby________________________________________
7. Undosquaringby_______________________________then______________________
SET Topic:Linearfunctionsandtheirinverses
CarlosandClaritahaveapetsittingbusiness.Whentheyweretryingtodecidehowmanyeachof
dogsandcatstheycouldfitintotheiryard,theymadeatablebasedonthefollowinginformation.
Catpensrequire6ft2ofspace,whiledogrunsrequire24ft2.CarlosandClaritahaveupto360ft2
availableinthestorageshedforpensandruns,whilestillleavingenoughroomtomovearoundthe
cages.Theymadeatableofallofthecombinationsofcatsanddogstheycouldusetofillthespace.
Theyquicklyrealizedthattheycouldfitin4catsinthesamespaceasonedog.
x5= −2
x +17 = 20
x = 6
x +1( )3 = 2
x4 = 81
x − 9( )2 = 49
READY, SET, GO! Name PeriodDate
4
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.1
1.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
cats 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60
dogs 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
8.Usetheinformationinthetabletowrite5orderedpairsthathavecatsastheinputvalue
anddogsastheoutputvalue.
9.Writeanexplicitequationthatshowshowmanydogstheycanaccommodatebasedonhow
manycatstheyhave.(Thenumberofdogs“d”willbeafunctionofthenumberofcats“c”or
! = #(%).)
10.Usetheinformationinthetabletowrite5orderedpairsthathavedogsastheinputvalue
andcatsastheoutputvalue.
11.Writeanexplicitequationthatshowshowmanycatstheycanaccommodatebasedonhow
manydogstheyhave.(Thenumberofcats“c”willbeafunctionofthenumberofdogs“d”
or% = '(!).)
Baseyouranswersin#12and#13onthetableatthetopofthepage.
12.Lookbackatproblem8andproblem10.Describehowtheorderedpairsaredifferent.
13.a)Lookbackattheequationyouwroteinproblem9.Describethedomainfor! = #(%).
b)Describethedomainfortheequation% = '(!)thatyouwroteinproblem11.
c)Whatistherelationshipbetweenthem?
5
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.1
1.1
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
GO Topic:Usingfunctionnotationtoevaluateafunction.
Thefunctions aredefinedbelow.
Calculatetheindicatedfunctionvaluesinthefollowingproblems.Simplifyyouranswers.
14.
15. 16. 17.
18.
19. 20. 20.)(* + ,)
22.
23. 24. 25.
f x( ), g x( ), and h x( )f x( ) = x g x( ) = 5x −12 h x( ) = x2 + 4x − 7
f 10( ) f −2( ) f a( ) f a + b( )
g 10( ) g −2( ) g a( )
h 10( ) h −2( ) h a( ) h a + b( )
6
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
1.2 Flipping Ferraris
A Solidify Understanding Task
Whenpeoplefirstlearntodrive,theyareoftentoldthatthefastertheyaredriving,thelongeritwilltaketostop.So,whenyou’redrivingonthefreeway,youshouldleavemorespacebetweenyourcarandthecarinfrontofyouthanwhenyouaredrivingslowlythroughaneighborhood.Haveyoueverwonderedabouttherelationshipbetweenhowfastyouaredrivingandhowfaryoutravelbeforeyoustop,afterhittingthebrakes?
1. Thinkaboutitforaminute.Whatfactorsdoyouthinkmightmakeadifferenceinhowfaracartravelsafterhittingthebrakes?
Therehasactuallybeenquiteabitofexperimentalworkdone(mostlybypolicedepartmentsandinsurancecompanies)tobeabletomathematicallymodeltherelationshipbetweenthespeedofacarandthebrakingdistance(howfarthecargoesuntilitstopsafterthedriverhitsthebrakes).
2. Imagineyourdreamcar.MaybeitisaFerrari550Maranello,asuper-fastItaliancar.Experimentshaveshownthatonsmooth,dryroads,therelationshipbetweenthebrakingdistance(d)andspeed(s)isgivenby!(#) = 0.03#) .Speedisgiveninmiles/hourandthedistanceisinfeet.a) Howmanyfeetshouldyouleavebetweenyouandthecarinfrontofyouifyouare
drivingtheFerrariat55mi/hr?
b) Whatdistanceshouldyoukeepbetweenyouandthecarinfrontofyouifyouaredrivingat100mi/hr?
c) Ifanaveragecarisabout16feetlong,abouthowmanycarlengthsshouldyouhavebetweenyouandthatcarinfrontofyouifyouaredriving100mi/hr?
CC B
Y Da
rren
Price
ht
tps:/
/flic
.kr/
p/qv
LUQY
7
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
d) Itmakessensetoalotofpeoplethatifthecarismovingatsomespeedandthengoestwiceasfast,thebrakingdistancewillbetwiceasfar.Isthattrue?Explainwhyorwhynot.
3.Graphtherelationshipbetweenbrakingdistanced(s),andspeed(s),below.
4.AccordingtotheFerrariCompany,themaximumspeedofthecarisabout217mph.UsethistodescribeallthemathematicalfeaturesoftherelationshipbetweenbrakingdistanceandspeedfortheFerrarimodeledby!(#) = 0.03#) .
5.WhatifthedriveroftheFerrari550wascruisingalongandsuddenlyhitthebrakestostopbecauseshesawacatintheroad?Sheskiddedtoastop,andfortunately,missedthecat.Whenshegotoutofthecarshemeasuredtheskidmarksleftbythecarsothatsheknewthatherbrakingdistancewas31ft.
a)Howfastwasshegoingwhenshehitthebrakes?
b)Ifshedidn’tseethecatuntilshewas15feetaway,whatisthefastestspeedshecouldbetravelingbeforeshehitthebrakesifshewantstoavoidhittingthecat?
8
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
6.Partofthejobofpoliceofficersistoinvestigatetrafficaccidentstodeterminewhatcausedtheaccidentandwhichdriverwasatfault.Theymeasurethebrakingdistanceusingskidmarksandcalculatespeedsusingthemathematicalrelationshipsjustlikewehavehere,althoughtheyoftenusedifferentformulastoaccountforvariousfactorssuchasroadconditions.Let’sgobacktotheFerrarionasmooth,dryroadsinceweknowtherelationship.Createatablethatshowsthespeedthecarwastravelingbaseduponthebrakingdistance.
7.Writeanequationofthefunctions(d)thatgivesthespeedthecarwastravelingforagivenbrakingdistance.
8.Graphthefunctions(d)anddescribeitsfeatures.
9.Whatdoyounoticeaboutthegraphofs(d)comparedtothegraphofd(s)?Whatistherelationshipbetweenthefunctionsd(s)ands(d)?
9
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
10.Considerthefunction!(#) = 0.03#)overthedomainofallrealnumbers,notjustthedomainofthisproblemsituation.Howdoesthegraphchangefromthegraphofd(s)inquestion#3?
11.Howdoeschangingthedomainofd(s)changethegraphoftheinverseofd(s)?
12.Istheinverseofd(s)afunction?Justifyyouranswer.
10
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.2
1.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
READY Topic:SolvingforavariableSolveforx.
1. 17 = 5% + 2
2.2%( − 5 = 3%( − 12% +31
3.11 = √2% + 1
4.√%( + % − 2 = 25.−4 = √5% + 1- 6.√352- = √7%( + 9-
7.30 = 243 8.50 = 11(2 9.40 = 1
3(
SET Topic:Exploringinversefunctions
10.Studentsweregivenasetofdatatograph.Aftertheyhadcompletedtheirgraphs,each
studentsharedhisgraphwithhisshoulderpartner.WhenEthanandEmmasaweach
other’sgraphs,theyexclaimedtogether,“Yourgraphiswrong!”Neithergraphiswrong.
ExplainwhatEthanandEmmahavedonewiththeirdata.
Ethan’sgraph
Emma’sgraph
READY, SET, GO! Name PeriodDate
11
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.2
1.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
11.DescribeasequenceoftransformationsthatwouldtakeEthan’sgraphontoEmma’s.
12.Abaseballishitupwardfromaheightof3feetwith
aninitialvelocityof80feetpersecond(about55mph).Thegraphshowstheheightoftheballatanygivensecondduringitsflight.Usethegraphtoanswerthequestionsbelow.
a. Approximatethetimethattheballisatitsmaximumheight.
b. Approximatethetimethattheballhitstheground.
c. Atwhattimeistheball67feetabovetheground?
d. Makeanewgraphthatshowsthetimewhentheballisatthegivenheights.
e. Isyournewgraphafunction?Explain.
6
7
f
t
3
f
t
12
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.2
1.2
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
GO Topic:Usingfunctionnotationtoevaluateafunction
Thefunctions aredefinedbelow.
Calculatetheindicatedfunctionvalues.Simplifyyouranswers.
13.4(7) 14.4(−9) 15.4(7) 16.4(7 − 8)
17.9(7) 18.9(−9) 19.9(7) 20.9(7 − 8)
21.ℎ(7) 22.ℎ(−9) 23.ℎ(7) 24.ℎ(7 − 8)
Noticethatthenotationf(g(x))isindicatingthatyoureplacexinf(x)withg(x).
Simplifythefollowing.
25.f(g(x)) 26.f(h(x)) 27.g(f(x))
f x( ), g x( ), and h x( )
f x( ) = 3x g x( ) = 10x + 4 h x( ) = x2 − x
13
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
1.3 Tracking the Tortoise
A Solidify Understanding Task
Youmayrememberataskfromlastyearaboutthefamousracebetweenthetortoiseandthehare.Inthechildren’sstoryofthetortoiseandthehare,theharemocksthetortoiseforbeingslow.Thetortoisereplies,“Slowandsteadywinstherace.”Theharesays,“We’lljustseeaboutthat,”andchallengesthetortoisetoarace.
Inthetask,wemodeledthedistancefromthestartinglinethatboththetortoiseandtheharetravelledduringtherace.Todaywewillconsideronlythejourneyofthetortoiseintherace.
Becausethehareissoconfidentthathecanbeatthetortoise,hegivesthetortoisea1meterheadstart.Thedistancefromthestartinglineofthetortoiseincludingtheheadstartisgivenbythefunction:
!(#) = 2( (dinmetersandtinseconds)
Thetortoisefamilydecidestowatchtheracefromthesidelinessothattheycanseetheirdarlingtortoisesister,Shellie,provethevalueofpersistence.
1. Howfarawayfromthestartinglinemustthefamilybe,tobelocatedintherightplaceforShellietorunby5secondsafterthebeginningoftherace?After10seconds?
2. Describethegraphofd(t),Shellie’sdistanceattimet.Whataretheimportantfeaturesofd(t)?
CC B
Y Sc
ot N
elso
n ht
tps:/
/flic
.kr/
p/M
5GzR
d
14
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
3. Ifthetortoisefamilyplanstowatchtheraceat64metersawayfromShellie’sstartingpoint,howlongwilltheyhavetowaittoseeShellierunpast?
4. HowlongmusttheywaittoseeShellierunbyiftheystand1024metersawayfromher
startingpoint?
5. DrawagraphthatshowshowlongthetortoisefamilywillwaittoseeShellierunbyatagivenlocationfromherstartingpoint.
6. HowlongmustthefamilywaittoseeShellierunbyiftheystand220metersawayfrom
herstartingpoint?
7. Whatistherelationshipbetweend(t)andthegraphthatyouhavejustdrawn?Howdidyouused(t)todrawthegraphin#5?
15
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
8. Considerthefunction)(*) = 2+ .A) Whatarethedomainandrangeof)(*)?Is)(*)invertible?
B) Graph)(*)and)01(*)onthegridbelow.
C) Whatarethedomainandrangeof)01(*)?
9. If)(3) = 8,whatis)01(8)?Howdoyouknow?
10. If) 5167 = 1.414,whatis)01(1.414)?Howdoyouknow?
11. If)(;) = <whatis)01(<)?Willyouranswerchangeiff(x)isadifferentfunction?Explain.
16
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.3
1.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
READY Topic:Solvingexponentialequations.Solveforthevalueofx.
1. 5"#$ = 5&"'( 2. 7("'& = 7'&"#* 3. 4(" = 2&"'*
4. 3."'/ = 9&"'( 5. 8"#$ = 2&"#( 6. 3"#$ = $
*$
SET Topic:ExploringtheinverseofanexponentialfunctionInthefairytaleJackandtheBeanstalk,Jackplantsamagicbeanbeforehegoestobed.InthemorningJackdiscoversagiantbeanstalkthathasgrownsolarge,itdisappearsintotheclouds.Buthereisthepartofthestoryyouneverheard.Writtenonthebagcontainingthemagicbeanswasthisnote.Plant a magic bean in rich soil just as the sun is setting. Do not look at the plant site for 10 hours. (This is part of the magic.) After the bean has been in the ground for 1 hour, the growth of the sprout can be modeled by the function 2(4) = 36. (b in feet and t in hours) Jackwasagoodmathstudent,soalthoughheneverlookedathisbeanstalkduringthenight,heusedthefunctiontocalculatehowtallitshouldbeasitgrew.Thetableontherightshowsthecalculationshemadeeveryhalfhour.Hence,Jackwasnotsurprisedwhen,inthemorning,hesawthatthetopofthebeanstalkhaddisappearedintotheclouds.
Time(hours) Height(feet)1 31.5 5.22 92.5 15.63 273.5 46.84 814.5 140.35 2435.5 420.96 7296.5 1,262.77 2,1877.5 3,7888 6,5618.5 11,3649 19,6839.5 34,09210 59,049
READY, SET, GO! Name PeriodDate
17
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.3
1.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
7.DemonstratehowJackusedthemodel2(4) = 36 tocalculatehowhighthebeanstalkwouldbe
after6hourshadpassed.(Youmayusethetablebutwritedownwhereyouwouldputthenumbersinthefunctionifyoudidn’thavethetable.)
8.Duringthatsamenight,aneighborwasplayingwithhisdrone.Itwasprogrammedtohoverat
243ft.Howmanyhourshadthebeanstalkbeengrowingwhenitwasashighasthedrone?9.Didyouusethetableinthesamewaytoanswer#8asyoudidtoanswer#7? Explain.10.WhileJackwasmakinghistable,hewaswonderinghowtallthebeanstalkwouldbeafterthe
magical10hourshadpassed.Hequicklytypedthefunctionintohiscalculatortofindout.WritetheequationJackwouldhavetypedintohiscalculator.
11.Commercialjetsflybetween30,000ft.and36,000ft.Abouthowmanyhoursofgrowingcould
passbeforethebeanstalkmightinterferewithcommercialaircraft?Explainhowyougotyouranswer.
12.Usethetabletofind9(7)and9'$(11,364).13.Usethetabletofind9(9)and9'$(9).13.Explainwhyit’spossibletoanswersomeofthequestionsabouttheheightofthebeanstalkby
justpluggingthenumbersintothefunctionruleandwhysometimesyoucanonlyusethetable.
18
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.3
1.3
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
GO Topic:EvaluatingfunctionsThefunctions aredefinedbelow.
f(x) = −2x g(x) = 2x + 5 h(x) = x& + 3x − 10
Calculatetheindicatedfunctionvalues.Simplifyyouranswers.
14.f(a)
15.f(b&) 16.f(a + b) 17.fFG(H)I
18.g(a)
19.g(b&) 20.g
(a + b) 21.hFf(H)I
22.h(a)
23.h(b&) 24.h
(a + b) 25.hFG(H)I
f x( ), g x( ), and h x( )
19
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
1.4 Pulling a Rabbit Out of the Hat A Solidify Understanding Task Ihaveamagictrickforyou:
• Pickanumber,anynumber.• Add6• Multiplytheresultby2• Subtract12• Divideby2• Theansweristhenumberyoustartedwith!
Peopleareoftenmystifiedbysuchtricksbutthoseofuswhohavestudiedinverseoperationsandinversefunctionscaneasilyfigureouthowtheyworkandevencreateourownnumbertricks.Let’sgetstartedbyfiguringouthowinversefunctionsworktogether.
Foreachofthefollowingfunctionmachines,decidewhatfunctioncanbeusedtomaketheoutputthesameastheinputnumber.Describetheoperationinwordsandthenwriteitsymbolically.
Here’sanexample:
Input Output
!(#) = # + 8 !)*(#) = # − 8
# = 7 7 7 + 8 = 15
Inwords:Subtract8fromtheresult
CC B
Y Ch
ristia
n Ka
dlub
a
http
s://f
lic.k
r/p/
fwNc
q
20
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
1.
2.
Inwords:
Input Output
!(#) = 3# !)*(#) =
# = 7 7 3 ∙ 7 = 21
Input Output
!(#) = #/ !)*(#) =
# = 7 7 7/ = 49
Inwords:
21
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
3.
4.
5.
Inwords:
Input Output
!(#) = 23 !)*(#) =
# = 7 7 24 = 128
Input Output
!(#) = 2# − 5 !)*(#) =
# = 7 7 2 ∙ 7 − 5 = 9
Input Output
!(#) = # + 53 !)*(#) =
# = 7 7 7 + 53 = 4
Inwords:
22
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
6.
7.
Input Output
!(#) = (# − 3)/ !)*(#) =
# = 7 7 (7 − 3)/ = 16
Input Output
!(#) = 4 − √# !)*(#) =
# = 7 7 4 − √7
Inwords:
Inwords:
Inwords:
23
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
8.
9.Eachoftheseproblemsbeganwithx=7.Whatis thedifferencebetweenthe#usedin!(#)andthe#used in!)*(#)?
10.In#6,couldanyvalueof#beusedin!(#)andstillgivethesameoutputfrom!)*(#)?Explain.Whatabout#7?
11.Basedonyourworkinthistaskandtheothertasksinthismodulewhatrelationshipsdoyouseebetweenfunctionsandtheirinverses?
Inwords:
Input Output
!(#) = 23 − 10 !)*(#) =
# = 7 7 24 − 10 = 118
24
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.4
1.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
READY Topic:PropertiesofexponentsUsetheproductruleorthequotientruletosimplify.Leaveallanswersinexponentialformwithonlypositiveexponents.
1. 3" ∙ 3$
2.7& ∙ 7" 3.10)* ∙ 10+ 4. 5- ∙ 5)"
5. .&.$
6. 2" ∙ 2)0 ∙ 2 7. 1221)$ 8. +3
+4
9.-5-
10.0305 11.
+67+65 12. 8
69
83
SET Topic:Inversefunction13. Giventhefunctions:(<) = √< − 1BCDE(<) = <& + 7:
a.Calculate:(16)BCDE(3).
b.Write:(16)asanorderedpair.
c.WriteE(3)asanorderedpair.
d.Whatdoyourorderedpairsfor:(16)andE(3)imply?
e.Find:(25).
f.Basedonyouranswerfor:(25),predictE(4).
g.FindE(4). Didyouranswermatchyourprediction?
h.Are:(<)BCDE(<)inversefunctions? Justifyyouranswer.
READY, SET, GO! Name PeriodDate
25
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.4
1.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
Matchthefunctioninthefirstcolumnwithitsinverseinthesecondcolumn.
:(<) :)2(<)16.:(<) = 3< + 5
a.:)2(<) = KLE$<
17.:(<) = <$ b.:)2(<) = √<9
18.:(<) = √< − 33 c.:)2(<) = M)$0
19.:(<) = <0 d.:)2(<) = M0 − 5
20.:(<) = 5M e.:)2(<) = KLE0<
21.:(<) = 3(< + 5) f.:)2(<) = <$ + 3
22.:(<) = 3M g.:)2(<) = √<3
GO Topic:Compositefunctionsandinverses
CalculateNOP(Q)RSTUPON(Q)Rforeachpairoffunctions.(Note:thenotation(: ∘ E)(<)BCD(E ∘ :)(<)meansthesamethingas:OE(<)RBCDEO:(<)R,respectively.)
23.:(<) = 2< + 5E(<) = M)$
&
24.:(<) = (< + 2)0E(<) = √<9 − 2
25.:(<) = 0* < + 6E(<) =
*(M)")0
26.:(<) = )0M + 2E(<) =
)0M)&
26
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.4
1.4
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
Matchthepairsoffunctionsabove(23-26)withtheirgraphs.Labelf(x)andg(x).
a. b.
c. d.
27.Graphtheliney=xoneachofthegraphsabove.Whatdoyounotice?
28.Doyouthinkyourobservationsaboutthegraphsin#27hasanythingtodowiththe
answersyougotwhenyoufound:OE(<)RBCDEO:(<)R?Explain.
29.Lookatgraphb.Shadethe2trianglesmadebythey-axis,x-axis,andeachline.Whatis
interestingaboutthesetwotriangles?
30.Shadethe2trianglesingraphd.Aretheyinterestinginthesameway?Explain.
27
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
1.5 Inverse Universe A Practice Understanding Task Youandyourpartnerhaveeachbeengivenadifferent
setofcards.Theinstructionsare:
1. Selectacardandshowittoyourpartner.2. Worktogethertofindacardinyourpartner’sset
ofcardsthatrepresentstheinverseofthefunctionrepresentedonyourcard.
3. Recordthecardsyouselectedandthereasonthatyouknowthattheyareinversesinthespacebelow.
4. Repeattheprocessuntilallofthecardsarepairedup.
*Forthistaskonly,assumethatalltablesrepresentpointsonacontinuousfunction.
Pair1: _____________________ Justificationofinverserelationship:____________________________________
Pair2: _____________________ Justificationofinverserelationship:____________________________________
Pair3: _____________________ Justificationofinverserelationship:____________________________________
Pair4: _____________________ Justificationofinverserelationship:____________________________________
Pair5: _____________________ Justificationofinverserelationship:____________________________________
CC B
Y ag
uayo
_sam
uel
http
s://f
lic.k
r/p/
uUq2
eR
28
ALGEBRA II // MODULE 1
FUNCTIONS AND THEIR INVERSES – 1.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Pair6: _____________________ Justificationofinverserelationship:____________________________________
Pair6: _____________________ Justificationofinverserelationship:____________________________________
Pair7: _____________________ Justificationofinverserelationship:____________________________________
Pair8: _____________________ Justificationofinverserelationship:____________________________________
Pair9: _____________________ Justificationofinverserelationship:____________________________________
Pair10:_____________________ Justificationofinverserelationship:____________________________________
29
A1
𝑓(𝑥) = {−2𝑥 − 2, −5 < 𝑥 < 0−2, 𝑥 ≥ 0
A3 Each input value, 𝑥, is squared and then 3 is added to the result. The domain of the function is [0,∞)
A5
x y -2 -3 2 3 0 0 6 5 4 4
−43
-2
A2 The function increases at a constant rate of 𝑎
𝑏 and the y-intercept is (0, c).
A4
A6
𝑦 = 3𝑥
A8
A7
x y -5 -125 -3 -27 -1 -1 1 1 3 27 5 125
A9
A10 Yasmin started a savings account with $5. At the end of each week, she added 3. This function models the amount of money in the account for a given week.
B1
𝑦 = log3 𝑥
B2
𝑓(𝑥) = { 23 𝑥, −3 < 𝑥 < 3
2𝑥 − 4, 𝑥 ≥ 3
B4
x y -216 -6 -64 -4 -8 -2 0 0 8 2
64 4 216 6
B3 The x-intercept is (c, 0) and the slope of the line is 𝑏
𝑎.
B6
x y 3 0 4 1 7 2
12 3 19 4 28 5 39 6
B5
B7
B8
𝒙 y -2 -3 -1 -2 0 1 1 6 2 13
B9
B10 The function is continuous and grows by an equal factor of 5 over equal intervals. The y-intercept is (0,1).
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.5
1.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
READY Topic:PropertiesofexponentsUsepropertiesofexponentstosimplifythefollowing.Writeyouranswersinexponentialformwithpositiveexponents.1.√"#$ ∙ √"&$
2.√"' ∙ √"( ∙ √")
3.√*) ∙ √*#' ∙ √+&,
4.√32, ∙ √9 ∙ √27'
5.√8( ∙ √16' ∙ √2)
6.(5#)&
7.(7#)78
8.(379)7:
9.;:<(
:=>&
SET Topic:RepresentationsofinversefunctionsWritetheinverseofthegivenfunctioninthesameformatasthegivenfunction.Functionf(x)
Inverse?78(")
10.x f(x)
-8 0
-4 3
0 6
4 9
8 12
10.
READY, SET, GO! Name PeriodDate
30
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.5
1.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
11. 12.
12.?(") = −2" + 4
13.?(") = EFG&"
14.
15.x ?(")
0 0
1 1
2 4
3 9
4 16
15.
31
ALGEBRA II // MODULE 1
FUNCTIONS AND INVERSES – 1.5
1.5
Mathematics Vision Project Licensed under the Creative Commons Attribution CC BY 4.0 mathematicsvisionproject.org
Needhelp?Visitwww.rsgsupport.org
GO Topic:CompositefunctionsCalculateHIJ(K)LMNOJIH(K)Lforeachpairoffunctions.
(Note:thenotation(? ∘ G)(")*QR(G ∘ ?)(")meanthesamething,respectively.)
16.?(") = 3" + 7; G(") = −4" − 11
17.?(") = −4" + 60; G(") = − 89" + 15
18.?(") = 10" − 5; G(") = #: " + 3
19.?(") = −#& " + 4; G(") = − &
# " + 6
20.Lookbackatyourcalculationsfor?IG(")L*QRGI?(")L.Twoofthepairsofequationsare
inversesofeachother.Whichonesdoyouthinktheyare?
Why?
32