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A guide to approaching AB Calculus AP Questions

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Page 1: AB Calculus Question Strategies

When you see…

Find the zeros

You think…

Page 2: AB Calculus Question Strategies

To find the zeros...To find the zeros...

Find roots. Set function = 0 Factor or use quadratic equation if quadratic. Graph to find zeros on calculator.

Page 3: AB Calculus Question Strategies

You think…

When you see…

Show that f(x) is even

Page 4: AB Calculus Question Strategies

Even functionEven function

f (-x) = f ( x)

y-axis symmetry

Page 5: AB Calculus Question Strategies

You think…

When you see…

Show that f(x) is odd

Page 6: AB Calculus Question Strategies

Odd functionOdd function

. f (-x) = -f (x)

OR -f(-x) = f(x)

origin symmetry

Page 7: AB Calculus Question Strategies

You think…

When you see…

Show that exists lim ( )x a

f x

Page 8: AB Calculus Question Strategies

Show existsShow exists lim ( )x a

f x

Show that

xfxfaxax

limlim

Page 9: AB Calculus Question Strategies

You think…

When you see…

Find xfax

lim , calculator allowed

Page 10: AB Calculus Question Strategies

Find Limit with calculator

.

Use TABLE [ASK], find y-values for x-values

close to a from left and right

Page 11: AB Calculus Question Strategies

You think…

When you see…

Find xfax

lim , no calculator

Page 12: AB Calculus Question Strategies

Find limits, no calculatorSubstitute x = a

1) limit is value if b

c , incl. 0

0; 0cc

2) DNE for 0

b

3) 0

0 DO MORE WORK!

a) rationalize radicals b) simplify complex fractions c) factor/reduce d) known trig limits

1. 0

sinlim 1x

x

x

2. 0

1 coslim 0x

x

x

e) piece-wise fcn: check if RH = LH at break .

Page 13: AB Calculus Question Strategies

You think…

When you see…

Find limx

f x ,

calculator allowed

Page 14: AB Calculus Question Strategies

Find limit with calculator

.

Use TABLE [ASK], find y-values for large values

of x, i.e. 999999999999

Page 15: AB Calculus Question Strategies

You think…

When you see…

Find limx

f x ,

no calculator

Page 16: AB Calculus Question Strategies

Find limit, no calculator

Ratios of rates of changes

1)fast

DNEslow

2) 0slow

fast

3) same

ratiosame

of coefficients .

Page 17: AB Calculus Question Strategies

You think…

When you see…

Find horizontal asymptotes of f(x)

Page 18: AB Calculus Question Strategies

Find horizontal asymptotes of f(x)Find horizontal asymptotes of f(x)

Find

xfx lim

and

xf

x lim

Page 19: AB Calculus Question Strategies

You think…

When you see…

Find vertical

asymptotes of f(x)

Page 20: AB Calculus Question Strategies

Find vertical asymptotes of f(x)Find vertical asymptotes of f(x)

Find where limx a

f x

1) Factor/reduce xf and set denominator = 0

2) ln x has VA at x = 0

Page 21: AB Calculus Question Strategies

You think…

When you see…

Find the domain

of f(x)

Page 22: AB Calculus Question Strategies

Find the domain of f(x)Find the domain of f(x)

Assume domain is

, . Domain restrictions: non-zero denominators, Square root of non-negative numbers, Log or ln of only positive numbers Real-world constraints

Page 23: AB Calculus Question Strategies

You think…

When you see…

Show that f(x) is continuous

Page 24: AB Calculus Question Strategies

..f(x) is continuousf(x) is continuous

Show that

1) xfax

lim exists

2) af exists

3) afxfax

lim

Page 25: AB Calculus Question Strategies

You think…

When you see…

Find the slope of the tangent line to f(x) at x = a

Page 26: AB Calculus Question Strategies

Slope of tangent line

. Find derivative maf

Page 27: AB Calculus Question Strategies

When you see…

Find equation of the line tangent to f(x) at (a, b)

You think…

Page 28: AB Calculus Question Strategies

Equation of the tangent lineEquation of the tangent line

maf and use y b m x a

sometimes need to find b f a

Page 29: AB Calculus Question Strategies

You think…

When you see…

Find equation of the line normal to f(x) at (a, b)

Page 30: AB Calculus Question Strategies

Equation of the normal lineEquation of the normal line

Same as previous but

afm

1

Page 31: AB Calculus Question Strategies

You think…

When you see…

Find the average rate of change of f(x) at [a, b]

Page 32: AB Calculus Question Strategies

Average rate of change of f(x)Average rate of change of f(x)

Find

f (b) - f ( a)

b - a

Page 33: AB Calculus Question Strategies

You think…

When you see…

Show that there exists a c in ba, such that f c n

Page 34: AB Calculus Question Strategies

Intermediate Value Theorem (IVT)

Confirm that xf is continuous on ba, , then show that

( ) ( )f a n f b .

Page 35: AB Calculus Question Strategies

You think…

When you see…

Find the interval where f(x) is increasing

Page 36: AB Calculus Question Strategies

ff(x) increasing(x) increasing

Find xf , set both numerator and denominator to zero to find critical points, make sign chart of

xf and determine where xf is positive. Closed interval, unless f(x) DNE.

Page 37: AB Calculus Question Strategies

You think…

When you see…

Find the interval where the slope of f (x) is increasing

Page 38: AB Calculus Question Strategies

Slope of Slope of f f (x) is increasing(x) is increasing

Find the derivative of f ’(x) = f “ (x) Set numerator and denominator = 0 to find critical points Make sign chart of f “ (x)

Determine where f “ (x) is positive

Also, think f(x) is CONCAVE UP

Page 39: AB Calculus Question Strategies

You think…

When you see…

Find the instantaneous rate of change of f(x)

on [a, b]

Page 40: AB Calculus Question Strategies

Instantaneous rate of change of f(x)Instantaneous rate of change of f(x)

Find f ‘ ( a)

Page 41: AB Calculus Question Strategies

You think…

When you see…

Given s(t) (position function), find v(t)

Page 42: AB Calculus Question Strategies

Given position s(t), find v(t)Given position s(t), find v(t)

Find tstv

Page 43: AB Calculus Question Strategies

You think…

When you see…

Find f ’(x) by the limit definition

Page 44: AB Calculus Question Strategies

Find f Find f ‘‘( x) by definition( x) by definitionfrequently asked backwardsfrequently asked backwards

ax

afxfaf

h

xfhxfxf

ax

h

lim

or lim0

Page 45: AB Calculus Question Strategies

You think…

When you see…

Find the average velocity of a particle

on [a, b]

Page 46: AB Calculus Question Strategies

Find the average rate of change on Find the average rate of change on [a,b][a,b]

Find

v ta

b

dt

b as b s a b a

Depending on if you know s(t) or v(t)

Page 47: AB Calculus Question Strategies

You think…

When you see…

Given v(t), determine if a particle is speeding up at

t = k

Page 48: AB Calculus Question Strategies

Given v(t), determine if the particle is Given v(t), determine if the particle is speeding up at t = kspeeding up at t = k

Find v (k) and a (k). If signs match, the particle is speeding up. If signs opposite, the particle is slowing down

Page 49: AB Calculus Question Strategies

You think…

When you see…

Given a graph of

find where f(x) is

increasing

'( )f x

Page 50: AB Calculus Question Strategies

Given a graph of f ‘(x) , find where f(x) is Given a graph of f ‘(x) , find where f(x) is increasingincreasing

Make a sign chart of xf

Determine where xf is positive (above x-axis)

Page 51: AB Calculus Question Strategies

You think…

When you see…

Given a table of x and xf on selected values between a and b, estimate cf

where c is between a and b.

Page 52: AB Calculus Question Strategies

Straddle c, using a value, k, greater than c and a value, h, less than c.

so hk

hfkfcf

Page 53: AB Calculus Question Strategies

You think…

When you see…Given a graph of xf , find where xf has a relative maximum

Page 54: AB Calculus Question Strategies

Relative maximum

. Identify where 0f x crosses the x-axis from above to below OR where xf is discontinuous and jumps from above to below the

x-axis

Page 55: AB Calculus Question Strategies

You think…

When you see…Given a graph of xf ,

find where xf is concave down

Page 56: AB Calculus Question Strategies

Concave Down

. Identify where xf is decreasing

Page 57: AB Calculus Question Strategies

You think…

When you see…Given a graph of xf ,

find where xf has point(s) of inflection

Page 58: AB Calculus Question Strategies

Points of Inflection

. Identify where xf changes from increasing to decreasing or vice

versa

Page 59: AB Calculus Question Strategies

You think…

When you see…

Show that a piecewise function is differentiable at the point a where the function rule splits

Page 60: AB Calculus Question Strategies

Show a piecewise function is Show a piecewise function is

differentiable at x=adifferentiable at x=a

First, be sure that the function is continuous at

ax by evaluating a in both parts

Take the derivative of each piece and show that

xfxfaxax

limlim

Page 61: AB Calculus Question Strategies

You think…

When you see…

Given a graph of xf and 1h x f x , find 'h a

Page 62: AB Calculus Question Strategies

Derivative of Inverse Function

.

Find the point where a is the y-value on xf , sketch a tangent

line and estimate 'f b at the point,

then

1'

'h a

f b

Page 63: AB Calculus Question Strategies

You think…

When you see…

Given the equation for xf and 1h x f x , find

'h a

Page 64: AB Calculus Question Strategies

Derivative of the inverse of f(x)Derivative of the inverse of f(x)

Understand that the point ,a b is on h x so the point ,b a is on f x . So find b where f b a

1

''

h af b

Page 65: AB Calculus Question Strategies

You think…

When you see…Given the equation

for xf , find its derivative algebraically

Page 66: AB Calculus Question Strategies

Derivative Rules. 1) know product/quotient/chain rules 2) know derivatives of basic functions

a. Power Rule: polynomials, radicals, rationals

b. ;x xe b

c. ln ; logbx x

d. sin ;cos ; tanx x x

e. 1arcsin ;arccos ;arctan ;sin ;x x x x etc

Page 67: AB Calculus Question Strategies

You think…

When you see…Given a relation of x and

y, find dy

dx algebraically

Page 68: AB Calculus Question Strategies

Implicit Differentiation

Find the derivative of each term, using product/quotient/chain appropriately,

especially, chain rule: every derivative of y

is multiplied by dy

dx ; then group all dy

dx terms

on one side; factor out dy

dx and solve.

Page 69: AB Calculus Question Strategies

You think…

When you see…

Find the derivative off(g(x))

Page 70: AB Calculus Question Strategies

Chain RuleChain Rule

xgxgf

Page 71: AB Calculus Question Strategies

You think…

When you see…

Find the minimum value of a function

Page 72: AB Calculus Question Strategies

Minimum value of a functionMinimum value of a function

Solve 0f x or DNE, make a sign chart, find sign change from negative to positive for relative minimums and evaluate those candidates along with endpoints back into

xf and choose the smallest. NOTE: be careful to confirm that xf exists for any x-values that make 'f x

DNE.

Page 73: AB Calculus Question Strategies

You think…

When you see…

Find the minimum slope of a function

Page 74: AB Calculus Question Strategies

Minimum slope of a functionMinimum slope of a function

Solve " 0f x or DNE, make a sign chart, find sign change from negative to positive for

relative minimums and evaluate those candidates along with endpoints back into

'f x and choose the smallest. NOTE: be careful to confirm that xf exists

for any x-values that make "f x DNE.

Page 75: AB Calculus Question Strategies

You think…

When you see…

Find critical numbers

Page 76: AB Calculus Question Strategies

Find critical numbersFind critical numbers

Express xf as a fraction and solve for

numerator and denominator each equal to zero.

Page 77: AB Calculus Question Strategies

You think…

When you see…

Find the absolute maximum of f(x)

Page 78: AB Calculus Question Strategies

Find the absolute minimum of f(x)Find the absolute minimum of f(x)

Solve 0f x or DNE, make a sign chart, find sign change from positive to

negative for relative maximums and evaluate those candidates into xf , also

find xfx lim and xf

x lim ; choose the

largest.

Page 79: AB Calculus Question Strategies

You think…

When you see…

Show that there exists a c in ba, such that ' 0f c

Page 80: AB Calculus Question Strategies

Confirm that f is continuous and differentiable on the interval. Find k and j in ba, such that f k f j , then

there is some c in ,k j such that

f c 0.

Rolle’s Theorem

Page 81: AB Calculus Question Strategies

You think…

When you see…

Show that there exists a c in ba, such that 'f c m

Page 82: AB Calculus Question Strategies

Mean Value Theorem

Confirm that f is continuous and differentiable on the interval. Find k

and j in ba, such that

.f k f j

mk j

,

then there is some c in ,k j such that .f c m

Page 83: AB Calculus Question Strategies

You think…

When you see…

Find the range

of f(x) on [a, b]

Page 84: AB Calculus Question Strategies

Find the range of f(x) on [a,b]Find the range of f(x) on [a,b]

Use max/min techniques to find values at relative max/mins. Also compare f a and f b

(endpoints)

Page 85: AB Calculus Question Strategies

You think…

When you see…

Find the range

of f(x) on ( , )

Page 86: AB Calculus Question Strategies

Use max/min techniques to find relativemax/mins.

Then examine

limx

f x .

Find the range of f(x) onFind the range of f(x) on ,

Page 87: AB Calculus Question Strategies

You think…

When you see…Find the locations of relative extrema of

xf given both 'f x and "f x .

Particularly useful for relations of x and y where a sign chart would be difficult.

Page 88: AB Calculus Question Strategies

Second Derivative Test

.

Find where ' 0 OR DNEf x then check the

value of "f x there. If "f x is positive, xf

has a relative minimum. If "f x is negative, xf has a relative minimum.

Page 89: AB Calculus Question Strategies

You think…

When you see…

Find inflection points of xf algebraically.

Page 90: AB Calculus Question Strategies

Find inflection pointsFind inflection points

Express xf as a fraction and set both numerator and denominator equal to zero. Make sign chart of xf to find where

xf changes sign. (+ to – or – to +) NOTE: be careful to confirm that xf exists for any x-values that make "f x DNE.

Page 91: AB Calculus Question Strategies

You think…

When you see…

Show that the line bmxy is tangent to

xf at 1 1,x y

Page 92: AB Calculus Question Strategies

.y = mx+b is tangent to f(x) at a pointy = mx+b is tangent to f(x) at a point

Two relationships are required: same slope and point of intersection. Check that

1'm f x and that 1 1,x y is on both xf and the tangent line.

Page 93: AB Calculus Question Strategies

You think…

When you see…Find any horizontal

tangent line(s) to xf or a relation of x and y.

Page 94: AB Calculus Question Strategies

Horizontal tangent lineHorizontal tangent line

Write dy

dx as a fraction. Set the numerator equal to zero. NOTE: be careful to confirm that any values are on the curve. Equation of tangent line is y = b. May have to find b.

Page 95: AB Calculus Question Strategies

You think…

When you see…Find any vertical tangent

line(s) to xf or a relation of x and y.

Page 96: AB Calculus Question Strategies

Vertical tangent line to f(x)Vertical tangent line to f(x)

Write

dy

dx as a fraction. Set the denominator equal to zero.

NOTE: be careful to confirm that any values are on the curve.

Equation of tangent line is x = a. May have to find a.

Page 97: AB Calculus Question Strategies

You think…

When you see…

Approximate the value f(0.1) of by using the

tangent line to f at x = 0

Page 98: AB Calculus Question Strategies

Approximate f(0.1) using tangent line Approximate f(0.1) using tangent line to f(x) at x = 0to f(x) at x = 0

Find the equation of the tangent line to f using 11 xxmyy where 0fm and the point is 0,0 f . Then plug in 0.1 into this

line; be sure to use an approximate sign.

Alternative linearization formula: 'y f a x a f a

Page 99: AB Calculus Question Strategies

You think…

When you see…

Find rates of change for volume problems

Page 100: AB Calculus Question Strategies

Rates of Change of Volumes

.

Write the volume formula. Find dV

dt . Careful about product/ chain rules. Watch

positive (increasing measure)/negative (decreasing measure) signs for rates.

Page 101: AB Calculus Question Strategies

You think…

When you see…Find rates of change for Pythagorean Theorem

problems

Page 102: AB Calculus Question Strategies

Pythagorean Rates of Change

.

2 2 2x y z

2 2 2dx dy dz

x y zdt dt dt

; can reduce 2’s

Watch positive (increasing distance)/negative (decreasing distance) signs for rates.

Page 103: AB Calculus Question Strategies

You think…

When you see…

Find the average valueof xf on ba,

Page 104: AB Calculus Question Strategies

Average value of the functionAverage value of the function

Find 1

b

a

f x dxb a

Page 105: AB Calculus Question Strategies

You think…

When you see…

Find the average rate of change of xf on ba,

Page 106: AB Calculus Question Strategies

Average Rate of Change

.

f b f a

b a

Page 107: AB Calculus Question Strategies

You think…

When you see…

Given v(t), find the total distance a particle travels on [a, b]

Page 108: AB Calculus Question Strategies

Given v(t), find the total distance a Given v(t), find the total distance a particle travels on [a,b]particle travels on [a,b]

Find b

a

dttv

Page 109: AB Calculus Question Strategies

You think…

When you see…

Given v(t), find the change in position of a particle on [a, b]

Page 110: AB Calculus Question Strategies

Given v(t), find the change in position Given v(t), find the change in position of a particle on [a,b]of a particle on [a,b]

Find b

a

v t dt

Page 111: AB Calculus Question Strategies

You think…

When you see…

Given tv and initial position of a particle, find the position at t = a.

Page 112: AB Calculus Question Strategies

Given Given v(t)v(t) and the initial position of a and the initial position of a particle, find the position at particle, find the position at tt = = aa..

Find

0

0a

v t dt s

Read carefully: “starts at rest at the origin” means 0 0s and 0 0v

Page 113: AB Calculus Question Strategies

You think…

When you see…

dttfdx

d x

a

Page 114: AB Calculus Question Strategies

Fundamental TheoremFundamental Theorem

xf

Page 115: AB Calculus Question Strategies

You think…

When you see…

( )

g x

a

df t dt

dx

Page 116: AB Calculus Question Strategies

Fundamental Theorem, againFundamental Theorem, againChain Rule, tooChain Rule, too

( ) '( )f g x g x

Page 117: AB Calculus Question Strategies

You think…

When you see…

Find area using left Riemann sums

Page 118: AB Calculus Question Strategies

Area using left Riemann sumsArea using left Riemann sums

1210 ... nxxxxbaseANote: sketch a number line to visualize

Page 119: AB Calculus Question Strategies

You think…

When you see…

Find area using right Riemann sums

Page 120: AB Calculus Question Strategies

Area using right Riemann sumsArea using right Riemann sums

1 2 3 ... nA base x x x x

Note: sketch a number line to visualize

Page 121: AB Calculus Question Strategies

You think…

When you see…

Find area using midpoint rectangles

Page 122: AB Calculus Question Strategies

Area using midpoint rectanglesArea using midpoint rectangles

Typically done with a table of values. Be sure to use only values that are given. If you are given 6 sets of points, you can only do 3 midpoint rectangles. Note: sketch a number line to visualize

Page 123: AB Calculus Question Strategies

You think…

When you see…

Find area using trapezoids

Page 124: AB Calculus Question Strategies

Area using trapezoidsArea using trapezoids

nn xxxxxbase

A 1210 2...222

This formula only works when the base (width) is the same. Also trapezoid area is the average of LH and RH. If different widths, you have to do individual

trapezoids, 1 2

1

2A h b b

Page 125: AB Calculus Question Strategies

You think…

When you see…Describe how you can tell if rectangle or trapezoid approximations over- or under-

estimate area.

Page 126: AB Calculus Question Strategies

Over- or Under-estimates

Overestimate area: LH for decreasing; RH for increasing; and trapezoids for concave up

Underestimate area: LH for increasing; RH for decreasing and trapezoids for concave down

DRAW A PICTURE with 2 shapes.

.

Page 127: AB Calculus Question Strategies

You think…

When you see…

Given , find dxxfb

a

dxkxfb

a

Page 128: AB Calculus Question Strategies

Given area under a curve and vertical Given area under a curve and vertical shift, find the new area under the curveshift, find the new area under the curve

dxkdxxfdxkxfb

a

b

a

b

a

Page 129: AB Calculus Question Strategies

You think…

When you see…

Given , draw a

slope field dx

dy

Page 130: AB Calculus Question Strategies

Draw a slope field of dy/dxDraw a slope field of dy/dx

Use the given points

Plug them into dx

dy,

drawing little lines with theindicated slopes at the points.

Page 131: AB Calculus Question Strategies

You think…

When you see…

y is increasing proportionally to y

Page 132: AB Calculus Question Strategies

.y is increasing proportionally to yy is increasing proportionally to y

kydt

dy

integrating to

kty Ae

Page 133: AB Calculus Question Strategies

You think…

When you see…

Solve the differential equation …

Page 134: AB Calculus Question Strategies

Solve the differential equation...Solve the differential equation...

Separate the variables – x on one side, y on the other. The dx and dy must all be upstairs. Integrate each side, add C. Find C before solving for y,[unless ln y , then solve for y first and find A]. When solving for y, choose + or – (not both), solution will be a continuous function passing through the initial value.

Page 135: AB Calculus Question Strategies

You think…

When you see…

Given a base, cross sections perpendicular to

the x-axis that are squares

Page 136: AB Calculus Question Strategies

Semi-circular cross sections Semi-circular cross sections perpendicular to the x-axisperpendicular to the x-axis

The distance between the curves is the base of your square.

So the volume is 2b

a

f x g x dx

Page 137: AB Calculus Question Strategies

You think…

When you see…

Given the value of F(a) and the fact that the

anti-derivative of f is F, find F(b)

Page 138: AB Calculus Question Strategies

Given Given FF((aa)) and the that the and the that the anti-derivative of anti-derivative of ff is is FF, find , find FF((bb))

Usually, this problem contains an antiderivative you cannot do. Utilize the fact that if xF is the antiderivative of f,

then b

a

f x dx F b F a .

Solve for bF using the calculator to find the definite integral, then

( )b

a

F b f x dx F a

Page 139: AB Calculus Question Strategies

You think…

When you see…

Meaning of

b

a

f t dt

Page 140: AB Calculus Question Strategies

Meaning of the integral of f(t) from a to xMeaning of the integral of f(t) from a to x

The accumulation function –

Net (positive f(x) => total) amount of y –units for function xf

from x = a to x = b.

Page 141: AB Calculus Question Strategies

You think…

When you see…

Given v(t) and s(0), find the greatest distance from the origin of a particle on [a, b]

Page 142: AB Calculus Question Strategies

Given Given vv((tt)) and and ss(0)(0), find the greatest distance from , find the greatest distance from the origin of a particle on [the origin of a particle on [aa, , bb]]

Solve 0 OR DNEv t . Then integrate tv adding 0s to find ts . Finally, compare s(each candidate) and s(each endpoint). Choose greatest distance (it might be negative!)

Page 143: AB Calculus Question Strategies

When you see…

Given a water tank with g gallons initially being filled at

the rate of tF gallons/min and

emptied at the rate of tE gallons/min on 0,b , find

Page 144: AB Calculus Question Strategies

You think…

a) the amount of water in

the tank at m minutes

Page 145: AB Calculus Question Strategies

Amount of water in the tank at t minutesAmount of water in the tank at t minutes

0

m

g F t E t dt

Page 146: AB Calculus Question Strategies

You think…

b) the rate the water

amount is changing

at m

Page 147: AB Calculus Question Strategies

Rate the amount of water is changing at t = m

0

mdF t E t dt F m E m

dt

Page 148: AB Calculus Question Strategies

You think…

c) the time when the

water is at a minimum

Page 149: AB Calculus Question Strategies

The time when the water is at a minimumThe time when the water is at a minimum

Solve 0F t E t to find candidates, evaluate

candidates and endpoints as x a in

0

a

g F t E t dt , choose the minimum value

Page 150: AB Calculus Question Strategies

You think…

When you see…

Find the area between xf and g x with xf > g x on ba,

Page 151: AB Calculus Question Strategies

Area between f(x) and g(x) on [a,b]Area between f(x) and g(x) on [a,b]

dxxgxfAb

a

Page 152: AB Calculus Question Strategies

You think…

When you see…

Find the volume of the area between xf and g x with f x g x , rotated about the

x-axis.

Page 153: AB Calculus Question Strategies

Volume generated by rotating area between Volume generated by rotating area between f(x) and g(x) about the x-axisf(x) and g(x) about the x-axis

2 2b

a

A f x g x dx

Page 154: AB Calculus Question Strategies

You think…

When you see…

Given v(t) and s(0),

find s(t)

Page 155: AB Calculus Question Strategies

Given v(t) and s(0), find s(t)Given v(t) and s(0), find s(t)

0

0t

s t v x dx s

Page 156: AB Calculus Question Strategies

You think…

When you see…

Find the line x = c that divides the area under

f(x) on [a, b] into two equal areas

Page 157: AB Calculus Question Strategies

Find the x=c so the area under f(x) is Find the x=c so the area under f(x) is

divided equallydivided equally

dxxfdxxfb

c

c

a

1

2

c b

a a

f x dx f x dx

OR

Page 158: AB Calculus Question Strategies

You think…

When you see…

Find the volume given a base bounded by xf and g x with xf > g x and cross

sections perpendicular to the x-axis are semi-circles

Page 159: AB Calculus Question Strategies

Semi-circular cross sections Semi-circular cross sections perpendicular to the x-axisperpendicular to the x-axis

The distance between the curves is the diameter of your circle. So the volume

is 2

1

2 2

b

a

f x g xdx