Every problem in the chapter beside the book’s answer, a chapter at a time as you scroll.

Chapter 12: Introduction to Calculus

188 problems · 39 figures

Try It #1 §12.1 source ↗

For the following limit, define a,f(x), and L.

lim x→5 ( 2 x 2 −4 )=46

Answer

a=5, f( x )=2 x 2 −4, and L=46.

Try It #2 §12.1 source ↗

Using the graph of the function y=f( x ) shown in Figure 8, estimate the following limits.

ⓐ limx→0-f(x)

ⓑ limx→0+f(x)

ⓒ limx→0f(x)

ⓓ limx→2-f(x)

ⓔ limx→2+f(x)

ⓕ limx→2f(x)

ⓖ limx→4-f(x)

ⓗ limx→4+f(x)

ⓘ limx→4f(x)

Graph of a piecewise function that has three segments: 1) negative infinity to 0, 2) 0 to 2, and 3) 2 to positive inifnity, which has a discontinuity at (4, 4) Figure 8

Answer

a. 0; b. 2; c. does not exist; d. −2; e. 0; f. does not exist; g. 4; h. 4; i. 4

Try It #3 §12.1 source ↗

Numerically estimate the limit of the following function by making a table:

lim x→0 ( 20sin(x) 4x )

Answer

lim x→0 ( 20sin(x) 4x )= 5

Table showing that f(x) approaches 5 from either side as x approaches 0 from either side.

Try It #4 §12.1 source ↗

Numerically estimate the following limit: lim x→0 ( sin( 2 x ) ).

Answer

does not exist

12.1-1 §12.1 source ↗

Explain the difference between a value at x=a and the limit as x approaches a.

Answer

The value of the function, the output, at x=a is f( a ). When the lim x→a f( x ) is taken, the values of x get infinitely close to a but never equal a. As the values of x approach a from the left and right, the limit is the value that the function is approaching.

12.1-3 §12.1 source ↗

For the following exercises, estimate the functional values and the limits from the graph of the function f provided in Figure 14.

A piecewise function with discontinuities at x = -2, x = 1, and x = 4. Figure 14

lim x→− 2 − f(x)

Answer

–4

12.1-5 §12.1 source ↗

For the following exercises, estimate the functional values and the limits from the graph of the function f provided in Figure 14.

A piecewise function with discontinuities at x = -2, x = 1, and x = 4. Figure 14

lim x→−2 f(x)

Answer

–4

12.1-7 §12.1 source ↗

For the following exercises, estimate the functional values and the limits from the graph of the function f provided in Figure 14.

A piecewise function with discontinuities at x = -2, x = 1, and x = 4. Figure 14

lim x→ 1 − f(x)

Answer

2

12.1-9 §12.1 source ↗

For the following exercises, estimate the functional values and the limits from the graph of the function f provided in Figure 14.

A piecewise function with discontinuities at x = -2, x = 1, and x = 4. Figure 14

lim x→1 f(x)

Answer

does not exist

12.1-11 §12.1 source ↗

For the following exercises, estimate the functional values and the limits from the graph of the function f provided in Figure 14.

A piecewise function with discontinuities at x = -2, x = 1, and x = 4. Figure 14

lim x→ 4 − f(x)

Answer

4

12.1-13 §12.1 source ↗

For the following exercises, estimate the functional values and the limits from the graph of the function f provided in Figure 14.

A piecewise function with discontinuities at x = -2, x = 1, and x = 4. Figure 14

lim x→4 f(x)

Answer

does not exist

12.1-15 §12.1 source ↗

For the following exercises, draw the graph of a function from the functional values and limits provided.

lim x→ 0 − f(x)= 2, lim x→ 0 + f(x)= –3, lim x→2 f(x)= 2, f(0)=4, f(2)=–1, f(–3) does not exist.

Answer

Answers will vary.

12.1-16 §12.1 source ↗

For the following exercises, draw the graph of a function from the functional values and limits provided.

lim x→ 2 − f(x)= 0, lim x→ 2 + =–2, lim x→0 f(x)= 3, f(2)=5, f(0)

Answer

Answers will vary.

12.1-17 §12.1 source ↗

For the following exercises, draw the graph of a function from the functional values and limits provided.

lim x→ 2 − f(x)= 2, lim x→ 2 + f(x)= − 3, lim x→0 f(x)= 5, f(0)=1, f(1)=0

Answer

Answers will vary.

12.1-18 §12.1 source ↗

For the following exercises, draw the graph of a function from the functional values and limits provided.

lim x→ 3 − f(x)= 0, lim x→ 3 + f(x)= 5, lim x→5 f(x)= 0, f(5)=4, f(3) does not exist.

Answer

Answers will vary.

12.1-19 §12.1 source ↗

For the following exercises, draw the graph of a function from the functional values and limits provided.

lim x→4 f(x)= 6, lim x→ 6 + f(x)= − 1, lim x→0 f(x)= 5, f(4)=6, f(2)=6

Answer

Answers will vary.

12.1-20 §12.1 source ↗

For the following exercises, draw the graph of a function from the functional values and limits provided.

lim x→−3 f(x)= 2, lim x→ 1 + f(x)= − 2, lim x→3 f(x)= –4, f(–3)=0, f(0)=0

Answer

Answers will vary.

12.1-21 §12.1 source ↗

For the following exercises, draw the graph of a function from the functional values and limits provided.

lim x→π f(x)= π 2 , lim x→–π f(x)= π 2 , lim x→ 1 – f(x)= 0, f(π)= 2 , f(0) does not exist.

Answer

Answers will vary.

12.1-23 §12.1 source ↗

For the following exercises, use a graphing calculator to determine the limit to 5 decimal places as x approaches 0.

g(x)= ( 1+x ) 2 x

Answer

7.38906

12.1-25 §12.1 source ↗

For the following exercises, use a graphing calculator to determine the limit to 5 decimal places as x approaches 0.

i(x)= ( 1+x ) 4 x

Answer

54.59815

12.1-27 §12.1 source ↗

For the following exercises, use a graphing calculator to determine the limit to 5 decimal places as x approaches 0.

Based on the pattern you observed in the exercises above, make a conjecture as to the limit of f(x)= ( 1+x ) 6 x , g(x)= ( 1+x ) 7 x , and h(x)= ( 1+x ) n x .

Answer

e 6 ≈ 403.428794, e 7 ≈ 1096.633158, e n

12.1-29 §12.1 source ↗

For the following exercises, use a graphing utility to find graphical evidence to determine the left- and right-hand limits of the function given as x approaches a. If the function has a limit as x approaches a, state it. If not, discuss why there is no limit.

(x)={ 1 x+1 , if x=−2 (x+1) 2 , if x≠−2 a=−2

Answer

lim x→−2 f(x)= 1

12.1-31 §12.1 source ↗

For the following exercises, use numerical evidence to determine whether the limit exists at x=a. If not, describe the behavior of the graph of the function near x=a. Round answers to two decimal places.

f(x)= x 2 −x−6 x 2 −9 ; a= 3

Answer

lim x→3 ( x 2 −x−6 x 2 −9 )= 5 6 ≈ 0.83

12.1-33 §12.1 source ↗

For the following exercises, use numerical evidence to determine whether the limit exists at x=a. If not, describe the behavior of the graph of the function near x=a. Round answers to two decimal places.

f(x)= x 2 –1 x 2 –3x+2 ; a= 1

Answer

lim x→1 ( x 2 −1 x 2 −3x+2 )= − 2.00

12.1-35 §12.1 source ↗

For the following exercises, use numerical evidence to determine whether the limit exists at x=a. If not, describe the behavior of the graph of the function near x=a. Round answers to two decimal places.

f(x)= 10−10 x 2 x 2 −3x+2 ; a= 1

Answer

lim x→1 ( 10−10 x 2 x 2 −3x+2 )= 20.00

12.1-37 §12.1 source ↗

For the following exercises, use numerical evidence to determine whether the limit exists at x=a. If not, describe the behavior of the graph of the function near x=a. Round answers to two decimal places.

f(x)= x 4 x 2 +4x+1 ; a= − 1 2

Answer

lim x→ −1 2 ( x 4 x 2 +4x+1 ) does not exist. Function values decrease without bound as x approaches –0.5 from either left or right.

12.1-39 §12.1 source ↗

For the following exercises, use a calculator to estimate the limit by preparing a table of values. If there is no limit, describe the behavior of the function as x approaches the given value.

lim x→0 7tanx 3x

Answer

lim x→0 7tanx 3x = 7 3

Table shows as the function approaches 0, the value is 7 over 3 but the function is undefined at 0.

12.1-40 §12.1 source ↗

For the following exercises, use a calculator to estimate the limit by preparing a table of values. If there is no limit, describe the behavior of the function as x approaches the given value.

lim x→4 x 2 x−4

Answer

Table shows as the function approaches 4, the value does not exist since approaching the limit value from the left is negative infinity and approaching the limit value from the right is positive infinity.

12.1-43 §12.1 source ↗

For the following exercises, use a graphing utility to find numerical or graphical evidence to determine the left and right-hand limits of the function given as x approaches a. If the function has a limit as x approaches a, state it. If not, discuss why there is no limit.

lim x→0 e e − 1 x 2

Answer

lim x→0 e e − 1 x 2 = 1.0

12.1-45 §12.1 source ↗

For the following exercises, use a graphing utility to find numerical or graphical evidence to determine the left and right-hand limits of the function given as x approaches a. If the function has a limit as x approaches a, state it. If not, discuss why there is no limit.

lim x→−1 | x+1 | x+1

Answer

lim x→− 1 − | x+1 | x+1 = −(x+1) (x+1) = − 1 and lim x→− 1 + | x+1 | x+1 = (x+1) (x+1) = 1; since the right-hand limit does not equal the left-hand limit, lim x→−1 | x+1 | x+1 does not exist.

12.1-47 §12.1 source ↗

For the following exercises, use a graphing utility to find numerical or graphical evidence to determine the left and right-hand limits of the function given as x approaches a. If the function has a limit as x approaches a, state it. If not, discuss why there is no limit.

lim x→−1 1 ( x+1 ) 2

Answer

lim x→−1 1 ( x+1 ) 2 does not exist. The function increases without bound as x approaches −1 from either side.

12.1-49 §12.1 source ↗

For the following exercises, use a graphing utility to find numerical or graphical evidence to determine the left and right-hand limits of the function given as x approaches a. If the function has a limit as x approaches a, state it. If not, discuss why there is no limit.

lim x→0 5 1− e 2 x

Answer

lim x→0 5 1− e 2 x does not exist. Function values approach 5 from the left and approach 0 from the right.

12.1-51 §12.1 source ↗

For the following exercises, use a graphing utility to find numerical or graphical evidence to determine the left and right-hand limits of the function given as x approaches a. If the function has a limit as x approaches a, state it. If not, discuss why there is no limit.

According to the Theory of Relativity, the mass m of a particle depends on its velocity v . That is

m= m o 1−( v 2 / c 2 )

where m o is the mass when the particle is at rest and c is the speed of light. Find the limit of the mass, m, as v approaches c − .

Answer

Through examination of the postulates and an understanding of relativistic physics, as v→c, m→∞. Take this one step further to the solution,

lim v→ c − m= lim v→ c − m o 1−( v 2 / c 2 ) =∞

Try It #1 §12.2 source ↗

Evaluate the following limit: lim x→−12 ( −2x+2 ).

Answer

26

Try It #2 §12.2 source ↗

Evaluate lim x→4 ( x 3 −5).

Answer

59

Try It #3 §12.2 source ↗

Evaluate the following limit: lim x→−1 ( x 4 −4 x 3 +5 ).

Answer

10

Try It #4 §12.2 source ↗

Evaluate the following limit: lim x→−4 ( 10x+36 ) 3 .

Answer

−64

Try It #5 §12.2 source ↗

Evaluate the following limit: lim x→7 ( x 2 −11x+28 7−x ).

Answer

−3

Try It #6 §12.2 source ↗

Evaluate lim x→−5 ( 1 5 + 1 x 10+2x ).

Answer

− 1 50

Try It #7 §12.2 source ↗

Evaluate the following limit: lim h→0 ( 16−h −4 h ).

Answer

− 1 8

Try It #8 §12.2 source ↗

Evaluate the following limit: lim x→3 ( x−3 x − 3 ).

Answer

2 3

Try It #9 §12.2 source ↗

Evaluate lim x→ 6 + 6−x | x−6 | .

Answer

−1

12.2-1 §12.2 source ↗

Give an example of a type of function f whose limit, as x approaches a, is f( a ).

Answer

If f is a polynomial function, the limit of a polynomial function as x approaches a will always be f( a ).

12.2-3 §12.2 source ↗

What does it mean to say the limit of f( x ) , as x approaches c , is undefined?

Answer

It could mean either (1) the values of the function increase or decrease without bound as x approaches c, or (2) the left and right-hand limits are not equal.

12.2-5 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→2 ( −5x x 2 −1 )

Answer

−10 3

12.2-7 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→3 ( x 2 −9 x−3 )

Answer

6

12.2-9 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→ 3 2 ( 6 x 2 −17x+12 2x−3 )

Answer

1 2

12.2-11 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→3 ( x 2 −9 x 2 −5x+6 )

Answer

6

12.2-13 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→3 ( x 2 +2x−3 x−3 )

Answer

does not exist

12.2-15 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim h→0 ( ( 2−h ) 3 −8 h )

Answer

−12

12.2-17 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim h→0 ( 5−h − 5 h )

Answer

− 5 10

12.2-19 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→9 ( x 2 −81 3− x )

Answer

−108

12.2-21 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→0 ( x 1+2x −1 )

Answer

1

12.2-23 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→4 ( x 3 −64 x 2 −16 )

Answer

6

12.2-25 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→ 2 + ( | x−2 | x−2 )

Answer

1

12.2-27 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→ 4 − ( | x−4 | 4−x )

Answer

1

12.2-29 §12.2 source ↗

For the following exercises, evaluate the limits algebraically.

lim x→4 ( | x−4 | 4−x )

Answer

does not exist

12.2-31 §12.2 source ↗

For the following exercise, use the given information to evaluate the limits: lim x→c f(x)= 3, lim x→c g(x)= 5.

lim x→c [ 2f(x)+ g(x) ]

Answer

6+ 5

12.2-33 §12.2 source ↗

For the following exercise, use the given information to evaluate the limits: lim x→c f(x)= 3, lim x→c g(x)= 5.

lim x→c f(x) g(x)

Answer

3 5

12.2-35 §12.2 source ↗

For the following exercises, evaluate the following limits.

lim x→2 sin( πx )

Answer

0

12.2-37 §12.2 source ↗

For the following exercises, evaluate the following limits.

f(x)={ 2 x 2 +2x+1, x≤0 x−3, x>0 ;  lim x→ 0 + f(x)

Answer

−3

12.2-39 §12.2 source ↗

For the following exercises, evaluate the following limits.

f(x)={ 2 x 2 +2x+1, x≤0 x−3, x>0 ;  lim x→0 f(x)

Answer

does not exist; right-hand limit is not the same as the left-hand limit.

12.2-41 §12.2 source ↗

For the following exercises, evaluate the following limits.

lim x→ 2 + (2x−[x])

Answer

2

12.2-43 §12.2 source ↗

For the following exercises, evaluate the following limits.

lim x→ 3 + x 2 x 2 −9

Answer

Limit does not exist; limit approaches infinity.

12.2-45 §12.2 source ↗

For the following exercises, find the average rate of change f(x+h)−f(x) h .

f(x)=2 x 2 −1

Answer

4x+2h

12.2-47 §12.2 source ↗

For the following exercises, find the average rate of change f(x+h)−f(x) h .

f(x)= x 2 + 4x− 100

Answer

2x+h+4

12.2-49 §12.2 source ↗

For the following exercises, find the average rate of change f(x+h)−f(x) h .

f(x)=cos(x)

Answer

cos(x+h)−cos(x) h

12.2-51 §12.2 source ↗

For the following exercises, find the average rate of change f(x+h)−f(x) h .

f(x)= 1 x

Answer

−1 x(x+h)

12.2-53 §12.2 source ↗

For the following exercises, find the average rate of change f(x+h)−f(x) h .

f(x)= x

Answer

−1 x+h + x

12.2-55 §12.2 source ↗

For the following exercises, find the average rate of change f(x+h)−f(x) h .

Find an equation that could be represented by Figure 4.

Graph of increasing function with a removable discontinuity at (-3, -1). Figure 4

Answer

f(x)= x 2 +5x+6 x+3

12.2-57 §12.2 source ↗

For the following exercises, refer to Figure 5.

Graph of increasing function from zero to positive infinity. Figure 5

What is the left-hand limit of the function as x approaches 0?

Answer

does not exist

12.2-59 §12.2 source ↗

For the following exercises, refer to Figure 5.

Graph of increasing function from zero to positive infinity. Figure 5

The height of a projectile is given by s(t)= − 64 t 2 + 192t Find the average rate of change of the height from t=1 second to t=1.5 seconds.

Answer

52

Try It #1 §12.3 source ↗

Identify all discontinuities for the following functions as either a jump or a removable discontinuity.

ⓐ f(x)= x 2 −6x x−6

ⓑ g(x)={ x , 0≤x<4 2x, x≥4

Answer

ⓐ removable discontinuity at x=6;

ⓑ jump discontinuity at x=4

Try It #2 §12.3 source ↗

Determine whether the function f(x)={ 1 x , x≤2 9x−11.5, x>2 is continuous at x=2.

Answer

No. The function is not continuous at x=2 because the left hand limit is 12 and the right hand limit is 6.5.

Try It #3 §12.3 source ↗

Determine whether the function f(x)= 9− x 2 x 2 −3x is continuous at x=3. If not, state the type of discontinuity.

Answer

No, the function is not continuous at x=3. There exists a removable discontinuity at x=3.

Try It #4 §12.3 source ↗

Determine where the function f(x)={ πx 4 ,x<2 π x ,    2≤x≤6 2πx,x>6 is discontinuous.

Answer

x=6

12.3-1 §12.3 source ↗

State in your own words what it means for a function f to be continuous at x=c.

Answer

Informally, if a function is continuous at x=c , then there is no break in the graph of the function at f( c ), and f( c ) is defined.

12.3-3 §12.3 source ↗

For the following exercises, determine why the function f is discontinuous at a given point a on the graph. State which condition fails.

f(x)= ln|x+ 3|, a= − 3

Answer

discontinuous at a=−3 ; f(−3) does not exist

12.3-5 §12.3 source ↗

For the following exercises, determine why the function f is discontinuous at a given point a on the graph. State which condition fails.

f(x)= x 2 −16 x+4 , a= − 4

Answer

removable discontinuity at a=−4 ; f(−4) is not defined

12.3-7 §12.3 source ↗

For the following exercises, determine why the function f is discontinuous at a given point a on the graph. State which condition fails.

f( x )={ x,x≠3 2x,x=3 a=3

Answer

Discontinuous at a=3 ; lim x→3 f(x)= 3, but f(3)=6 , which is not equal to the limit.

12.3-9 §12.3 source ↗

For the following exercises, determine why the function f is discontinuous at a given point a on the graph. State which condition fails.

f( x )={ 1 2−x , x≠2 3, x=2 a=2

Answer

lim x→2 f(x) does not exist.

12.3-11 §12.3 source ↗

For the following exercises, determine why the function f is discontinuous at a given point a on the graph. State which condition fails.

f( x )={ 3+x, x<1 x, x=1 x 2 , x>1     a=1

Answer

lim x→ 1 − f(x)= 4; lim x→ 1 + f(x)= 1. Therefore, lim x→1 f(x) does not exist.

12.3-13 §12.3 source ↗

For the following exercises, determine why the function f is discontinuous at a given point a on the graph. State which condition fails.

f( x )={ 3+2x, x<1 x, x=1 − x 2 , x>1     a=1

Answer

lim x→ 1 − f(x)= 5≠ lim x→ 1 + f(x)= − 1. Thus lim x→1 f(x) does not exist.

12.3-15 §12.3 source ↗

For the following exercises, determine why the function f is discontinuous at a given point a on the graph. State which condition fails.

f( x )={ x 2 −9 x+3 , x<−3 x−9, x=−3 1 x , x>−3     a=−3

Answer

lim x→− 3 − f(x)= − 6, lim x→− 3 + f(x)= − 1 3

Therefore, lim x→−3 f(x) does not exist.

12.3-17 §12.3 source ↗

For the following exercises, determine why the function f is discontinuous at a given point a on the graph. State which condition fails.

f(x)= x 2 −4 x−2 , a= 2

Answer

f( 2 ) is not defined.

12.3-19 §12.3 source ↗

For the following exercises, determine why the function f is discontinuous at a given point a on the graph. State which condition fails.

f(x)= x 3 −9x x 2 +11x+24 , a= − 3

Answer

f( −3 ) is not defined.

12.3-21 §12.3 source ↗

For the following exercises, determine why the function f is discontinuous at a given point a on the graph. State which condition fails.

f(x)= x |x| , a= 0

Answer

f( 0 ) is not defined.

12.3-23 §12.3 source ↗

For the following exercises, determine whether or not the given function f is continuous everywhere. If it is continuous everywhere it is defined, state for what range it is continuous. If it is discontinuous, state where it is discontinuous.

f(x)= x 3 − 2x− 15

Answer

Continuous on (−∞,∞)

12.3-25 §12.3 source ↗

For the following exercises, determine whether or not the given function f is continuous everywhere. If it is continuous everywhere it is defined, state for what range it is continuous. If it is discontinuous, state where it is discontinuous.

f( x )=2⋅ 3 x+4

Answer

Continuous on (−∞,∞)

12.3-27 §12.3 source ↗

For the following exercises, determine whether or not the given function f is continuous everywhere. If it is continuous everywhere it is defined, state for what range it is continuous. If it is discontinuous, state where it is discontinuous.

f(x)= | x−2 | x 2 −2x

Answer

Discontinuous at x=0 and x=2

12.3-29 §12.3 source ↗

For the following exercises, determine whether or not the given function f is continuous everywhere. If it is continuous everywhere it is defined, state for what range it is continuous. If it is discontinuous, state where it is discontinuous.

f( x )=2x+ 5 x

Answer

Discontinuous at x=0

12.3-31 §12.3 source ↗

For the following exercises, determine whether or not the given function f is continuous everywhere. If it is continuous everywhere it is defined, state for what range it is continuous. If it is discontinuous, state where it is discontinuous.

f(x)=ln x 2

Answer

Continuous on (0,∞)

12.3-33 §12.3 source ↗

For the following exercises, determine whether or not the given function f is continuous everywhere. If it is continuous everywhere it is defined, state for what range it is continuous. If it is discontinuous, state where it is discontinuous.

f(x)= x−4

Answer

Continuous on [4,∞)

12.3-35 §12.3 source ↗

For the following exercises, determine whether or not the given function f is continuous everywhere. If it is continuous everywhere it is defined, state for what range it is continuous. If it is discontinuous, state where it is discontinuous.

f(x)= x 2 + sin(x)

Answer

Continuous on (−∞,∞) .

12.3-37 §12.3 source ↗

For the following exercises, refer to Figure 15. Each square represents one square unit. For each value of a , determine which of the three conditions of continuity are satisfied at x=a and which are not.

Graph of a piecewise function where at x = -3 the line is disconnected, at x = 2 there is a removable discontinuity, and at x = 4 there is a removable discontinuity and f(4) exists. Figure 15

x=−3

Answer

1, but not 2 or 3

12.3-39 §12.3 source ↗

For the following exercises, refer to Figure 15. Each square represents one square unit. For each value of a , determine which of the three conditions of continuity are satisfied at x=a and which are not.

Graph of a piecewise function where at x = -3 the line is disconnected, at x = 2 there is a removable discontinuity, and at x = 4 there is a removable discontinuity and f(4) exists. Figure 15

x=4

Answer

1 and 2, but not 3

12.3-41 §12.3 source ↗

For the following exercises, use a graphing utility to graph the function f(x)= sin( 12π x ) as in Figure 16. Set the x-axis a short distance before and after 0 to illustrate the point of discontinuity.

Graph of the sinusodial function with a viewing window of [-10, 10] by [-1, 1]. Figure 16

Evaluate f(0).

Answer

f( 0 ) is undefined.

12.3-43 §12.3 source ↗

For the following exercises, use a graphing utility to graph the function f(x)= sin( 12π x ) as in Figure 16. Set the x-axis a short distance before and after 0 to illustrate the point of discontinuity.

Graph of the sinusodial function with a viewing window of [-10, 10] by [-1, 1]. Figure 16

What is the domain of f( x )?

Answer

(−∞,0)∪(0,∞)

12.3-45 §12.3 source ↗

For the following exercises, consider the function shown in Figure 17.

Graph of a piecewise function where at x = -1 the line is disconnected and at x = 1 there is a removable discontinuity. Figure 17

What condition of continuity is violated at these points?

Answer

At x=−1, the limit does not exist. At x=1, f( 1 ) does not exist.

At x=2, there appears to be a vertical asymptote, and the limit does not exist.

12.3-47 §12.3 source ↗

For the following exercises, consider the function shown in Figure 17.

Graph of a piecewise function where at x = -1 the line is disconnected and at x = 1 there is a removable discontinuity. Figure 17

Construct a function that passes through the origin with a constant slope of 1, with removable discontinuities at x=−7 and x=1.

Answer

x 3 +6 x 2 −7x ( x+7 )( x−1 )

12.3-49 §12.3 source ↗

For the following exercises, consider the function shown in Figure 17.

Graph of a piecewise function where at x = -1 the line is disconnected and at x = 1 there is a removable discontinuity. Figure 17

Find the limit lim x→1 f(x) and determine if the following function is continuous at x=1:

fx={ x 2 +4 x≠1 2 x=1

Answer

The function is discontinuous at x=1 because the limit as x approaches 1 is 5 and f( 1 )=2.

Try It #1 §12.4 source ↗

Find the average rate of change connecting the points ( −5,1.5 ) and (−2.5,9).

Answer

3

Try It #2 §12.4 source ↗

Find the derivative of the function f(x)=3 x 2 +7x at x=a.

Answer

f ′ (a)=6a+7

Try It #3 §12.4 source ↗

Find the derivative of the function f(x)= 10x+11 5x+4 at x=a.

Answer

f ′ (a)= −15 ( 5a+4 ) 2

Try It #4 §12.4 source ↗

Find the derivative of the function f( x )=9 x at x=9.

Answer

3 2

Try It #5 §12.4 source ↗

The position of the ball is given by s(t)= −16 t 2 + 64t+ 6. What is its velocity 2 seconds into flight?

Answer

0

Try It #6 §12.4 source ↗

Using the graph of the function f(x)= x 3 −3x shown in Figure 7, estimate: f(1), f ′ (1), f(0), and f ′ (0).

Graph of the function f(x) = x^3-3x with a viewing window of [-4. 4] by [-5, 7 Figure 7

Answer

−2 , 0, 0, −3

Try It #7 §12.4 source ↗

A runner runs along a straight east-west road. The function f( t ) gives how many feet eastward of her starting point she is after t seconds. Interpret each of the following as it relates to the runner.

ⓐ f( 0 )=0

ⓑ f( 10 )=150

ⓒ f ′ ( 10 )=15

ⓓ f ′ ( 20 )=−10

ⓔ f( 40 )=−100

Answer

ⓐ After zero seconds, she has traveled 0 feet.

ⓑ After 10 seconds, she has traveled 150 feet east.

ⓒ After 10 seconds, she is moving eastward at a rate of 15 ft/sec.

ⓓ After 20 seconds, she is moving westward at a rate of 10 ft/sec.

ⓔAfter 40 seconds, she is 100 feet westward of her starting point.

Try It #8 §12.4 source ↗

Determine where the function y=f( x ) shown in Figure 18 is continuous and differentiable from the graph.

Graph of a piecewise function with three pieces. Figure 18

Answer

The graph of f is continuous on ( −∞,1 )∪( 1,3 )∪( 3,∞ ). The graph of f is discontinuous at x=1 and x=3. The graph of f is differentiable on ( −∞,1 )∪( 1,3 )∪( 3,∞ ). The graph of f is not differentiable at x=1 and x=3.

Try It #9 §12.4 source ↗

Find the equation of a tangent line to the curve of the function f(x)= 5 x 2 − x+ 4 at x=2.

Answer

y=19x−16

Try It #10 §12.4 source ↗

A fireworks rocket is shot upward out of a pit 12 ft below the ground at a velocity of 60 ft/sec. Its height in feet after t seconds is given by s= − 16 t 2 + 60t− 12. What is its instantaneous velocity after 4 seconds?

Answer

–68 ft/sec, it is dropping back to Earth at a rate of 68 ft/s.

12.4-1 §12.4 source ↗

How is the slope of a linear function similar to the derivative?

Answer

The slope of a linear function stays the same. The derivative of a general function varies according to x. Both the slope of a line and the derivative at a point measure the rate of change of the function.

12.4-3 §12.4 source ↗

A car traveled 110 miles during the time period from 2:00 P.M. to 4:00 P.M. What was the car's average velocity? At exactly 2:30 P.M., the speed of the car registered exactly 62 miles per hour. What is another name for the speed of the car at 2:30 P.M.? Why does this speed differ from the average velocity?

Answer

Average velocity is 55 miles per hour. The instantaneous velocity at 2:30 p.m. is 62 miles per hour. The instantaneous velocity measures the velocity of the car at an instant of time whereas the average velocity gives the velocity of the car over an interval.

12.4-5 §12.4 source ↗

Suppose water is flowing into a tank at an average rate of 45 gallons per minute. Translate this statement into the language of mathematics.

Answer

The average rate of change of the amount of water in the tank is 45 gallons per minute. If f( x ) is the function giving the amount of water in the tank at any time t , then the average rate of change of f( x ) between t=a and t=b is f(a)+ 45(b−a).

12.4-7 §12.4 source ↗

For the following exercises, use the definition of derivative lim h→0 f(x+h)−f(x) h to calculate the derivative of each function.

f( x )=−2x+1

Answer

f ′ (x)=−2

12.4-9 §12.4 source ↗

For the following exercises, use the definition of derivative lim h→0 f(x+h)−f(x) h to calculate the derivative of each function.

f(x)= 2 x 2 + x− 3

Answer

f ′ (x)=4x+1

12.4-11 §12.4 source ↗

For the following exercises, use the definition of derivative lim h→0 f(x+h)−f(x) h to calculate the derivative of each function.

f( x )= −1 x−2

Answer

f ′ (x)= 1 (x−2) 2

12.4-13 §12.4 source ↗

For the following exercises, use the definition of derivative lim h→0 f(x+h)−f(x) h to calculate the derivative of each function.

f(x)= 5−2x 3+2x

Answer

−16 ( 3+2x ) 2

12.4-15 §12.4 source ↗

For the following exercises, use the definition of derivative lim h→0 f(x+h)−f(x) h to calculate the derivative of each function.

f(x)= 3 x 3 − x 2 + 2x+ 5

Answer

f ′ (x)= 9 x 2 − 2x+ 2

12.4-17 §12.4 source ↗

For the following exercises, use the definition of derivative lim h→0 f(x+h)−f(x) h to calculate the derivative of each function.

f(x)=5π

Answer

f ′ (x)=0

12.4-19 §12.4 source ↗

For the following exercises, find the average rate of change between the two points.

( 4,−3 ) and ( −2,−1 )

Answer

− 1 3

12.4-21 §12.4 source ↗

For the following exercises, find the average rate of change between the two points.

( 7,−2 ) and ( 7,10 )

Answer

undefined

12.4-23 §12.4 source ↗

For the following polynomial functions, find the derivatives.

f(x)= − 3 x 2 − 7x= 6

Answer

f ′ (x)=−6x−7

12.4-25 §12.4 source ↗

For the following polynomial functions, find the derivatives.

f(x)= 3 x 3 + 2 x 2 + x− 26

Answer

f ′ (x)= 9 x 2 + 4x+ 1

12.4-27 §12.4 source ↗

For the following functions, find the equation of the tangent line to the curve at the given point x on the curve.

f(x)= x 3 +1 x=2

Answer

y=12x−15

12.4-29 §12.4 source ↗

For the following exercise, find k such that the given line is tangent to the graph of the function.

f(x)= x 2 −kx, y=4x−9

Answer

k=−10 or k=2

12.4-31 §12.4 source ↗

For the following exercises, consider the graph of the function f and determine where the function is continuous/discontinuous and differentiable/not differentiable.


Graph of a piecewise function with three segments. The first segment goes from negative infinity to (-2, -1), an open point; the second segment goes from (-2, -4), an open point, to (0, 0), a closed point; the final segment goes from (0, 1), an open point, to positive infinity.

Answer

Discontinuous at x=−2 and x=0. Not differentiable at –2, 0, 2.

12.4-33 §12.4 source ↗

For the following exercises, consider the graph of the function f and determine where the function is continuous/discontinuous and differentiable/not differentiable.

Graph of a piecewise function with two segments. The first segment goes from (-4, 0), an open point to (5, -2), and the final segment goes from (5, 3), an open point, to positive infinity.

Answer

Discontinuous at x=5. Not differentiable at -4, –2, 0, 1, 3, 4, 5.

12.4-35 §12.4 source ↗

For the following exercises, use Figure 20 to estimate either the function at a given value of x or the derivative at a given value of x , as indicated.

Graph of an odd function with multiplicity of 2 with a turning point at (0, -2) and (2, -6). Figure 20

f( 0 )

Answer

f( 0 )=−2

12.4-37 §12.4 source ↗

For the following exercises, use Figure 20 to estimate either the function at a given value of x or the derivative at a given value of x , as indicated.

Graph of an odd function with multiplicity of 2 with a turning point at (0, -2) and (2, -6). Figure 20

f( 2 )

Answer

f( 2 )=−6

12.4-39 §12.4 source ↗

For the following exercises, use Figure 20 to estimate either the function at a given value of x or the derivative at a given value of x , as indicated.

Graph of an odd function with multiplicity of 2 with a turning point at (0, -2) and (2, -6). Figure 20

f ′ ( −1 )

Answer

f ′ ( −1 )=9

12.4-41 §12.4 source ↗

For the following exercises, use Figure 20 to estimate either the function at a given value of x or the derivative at a given value of x , as indicated.

Graph of an odd function with multiplicity of 2 with a turning point at (0, -2) and (2, -6). Figure 20

f ′ (1)

Answer

f ′ ( 1 )=−3

12.4-43 §12.4 source ↗

For the following exercises, use Figure 20 to estimate either the function at a given value of x or the derivative at a given value of x , as indicated.

Graph of an odd function with multiplicity of 2 with a turning point at (0, -2) and (2, -6). Figure 20

f ′ ( 3 )

Answer

f ′ ( 3 )=9

12.4-45 §12.4 source ↗

For the following exercises, use Figure 20 to estimate either the function at a given value of x or the derivative at a given value of x , as indicated.

Graph of an odd function with multiplicity of 2 with a turning point at (0, -2) and (2, -6). Figure 20

Numerically evaluate the derivative. Explore the behavior of the graph of f(x)= x 2 around x=1 by graphing the function on the following domains: [ 0.9,1.1 ] , [ 0.99,1.01 ] , [ 0.999,1.001 ] , and [0.9999,1.0001] . We can use the feature on our calculator that automatically sets Ymin and Ymax to the Xmin and Xmax values we preset. (On some of the commonly used graphing calculators, this feature may be called ZOOM FIT or ZOOM AUTO). By examining the corresponding range values for this viewing window, approximate how the curve changes at x=1, that is, approximate the derivative at x=1.

Answer

Answers vary. The slope of the tangent line near x=1 is 2.

12.4-47 §12.4 source ↗

For the following exercises, explain the notation in words. The volume f(t) of a tank of gasoline, in gallons, t minutes after noon.

f'(30)=−20

Answer

At 12:30 p.m., the rate of change of the number of gallons in the tank is –20 gallons per minute. That is, the tank is losing 20 gallons per minute.

12.4-49 §12.4 source ↗

For the following exercises, explain the notation in words. The volume f(t) of a tank of gasoline, in gallons, t minutes after noon.

f'(200)=30

Answer

At 200 minutes after noon, the volume of gallons in the tank is changing at the rate of 30 gallons per minute.

12.4-51 §12.4 source ↗

For the following exercises, explain the functions in words. The height, s , of a projectile after t seconds is given by s(t)= − 16 t 2 + 80t.

s(2)=96

Answer

The height of the projectile after 2 seconds is 96 feet.

12.4-53 §12.4 source ↗

For the following exercises, explain the functions in words. The height, s , of a projectile after t seconds is given by s(t)= − 16 t 2 + 80t.

s(3)=96

Answer

The height of the projectile at t=3 seconds is 96 feet.

12.4-55 §12.4 source ↗

For the following exercises, explain the functions in words. The height, s , of a projectile after t seconds is given by s(t)= − 16 t 2 + 80t.

s(0)= 0, s(5)= 0.

Answer

The height of the projectile is zero at t=0 and again at t=5. In other words, the projectile starts on the ground and falls to earth again after 5 seconds.

12.4-57 §12.4 source ↗

For the following exercises, the volume V of a sphere with respect to its radius r is given by V= 4 3 π r 3 .

Find the instantaneous rate of change of V when r= 3 cm.

Answer

36π

12.4-59 §12.4 source ↗

For the following exercises, the revenue generated by selling x items is given by R(x)= 2 x 2 + 10x.

Find R'(10) and interpret.

Answer

$50.00 per unit, which is the instantaneous rate of change of revenue when exactly 10 units are sold.

12.4-61 §12.4 source ↗

For the following exercises, the cost of producing x cellphones is described by the function C(x)= x 2 − 4x+ 1000.

Find the average rate of change in the total cost as x changes from x= 10 to x= 15.

Answer

$21 per unit

12.4-63 §12.4 source ↗

For the following exercises, the cost of producing x cellphones is described by the function C(x)= x 2 − 4x+ 1000.

Find the approximate marginal cost, when 20 cellphones have been produced, of producing the 21st cellphone.

Answer

$36

12.4-65 §12.4 source ↗

For the following exercises, use the definition for the derivative at a point x=a, lim x→a f(x)−f(a) x−a , to find the derivative of the functions.

f(x)= 5 x 2 − x+ 4

Answer

f'(x)=10a−1

12.4-67 §12.4 source ↗

For the following exercises, use the definition for the derivative at a point x=a, lim x→a f(x)−f(a) x−a , to find the derivative of the functions.

f(x)= −4 3− x 2

Answer

4 ( 3−x ) 2

12.R-1 §12.R source ↗

For the following exercises, use Figure 1.

Graph of a piecewise function with two segments. The first segment goes from (-1, 2), a closed point, to (3, -6), a closed point, and the second segment goes from (3, 5), an open point, to (7, 9), a closed point. Figure 1

lim x→ −1 + f(x)

Answer

2

12.R-3 §12.R source ↗

For the following exercises, use Figure 1.

Graph of a piecewise function with two segments. The first segment goes from (-1, 2), a closed point, to (3, -6), a closed point, and the second segment goes from (3, 5), an open point, to (7, 9), a closed point. Figure 1

lim x→−1 f(x)

Answer

does not exist

12.R-5 §12.R source ↗

For the following exercises, use Figure 1.

Graph of a piecewise function with two segments. The first segment goes from (-1, 2), a closed point, to (3, -6), a closed point, and the second segment goes from (3, 5), an open point, to (7, 9), a closed point. Figure 1

At what values of x is the function discontinuous? What condition of continuity is violated?

Answer

Discontinuous at x= − 1( lim x→a f(x) does not exist ),x=3(jump discontinuity), andx= 7( lim x→a f(x) does not exist).

12.R-7 §12.R source ↗

For the following exercises, with the use of a graphing utility, use numerical or graphical evidence to determine the left- and right-hand limits of the function given as x approaches a. If the function has limit as x approaches a, state it. If not, discuss why there is no limit.

f(x)={ | x |−1, if x≠1 x 3 , if x=1   a=1

Answer

lim x→−2 f(x)=0

12.R-9 §12.R source ↗

For the following exercises, with the use of a graphing utility, use numerical or graphical evidence to determine the left- and right-hand limits of the function given as x approaches a. If the function has limit as x approaches a, state it. If not, discuss why there is no limit.

f(x)={ x+3 , if x<1 − x 3 , if x>1   a=1

Answer

Does not exist

12.R-11 §12.R source ↗

For the following exercises, find the limits if lim x→c f(x)= −3 and lim x→c g(x)= 5.

lim x→c f(x) g(x)

Answer

-35

12.R-13 §12.R source ↗

For the following exercises, find the limits if lim x→c f(x)= −3 and lim x→c g(x)= 5.

lim x→ 0 + f(x),f(x)={ 3 x 2 +2x+1 5x+3    x>0 x<0

Answer

1

12.R-15 §12.R source ↗

For the following exercises, find the limits if lim x→c f(x)= −3 and lim x→c g(x)= 5.

lim x→ 3 + ( 3x−[x] )

Answer

6

12.R-17 §12.R source ↗

For the following exercises, evaluate the limits using algebraic techniques.

lim x→25 ( x 2 −625 x −5 )

Answer

500

12.R-19 §12.R source ↗

For the following exercises, evaluate the limits using algebraic techniques.

lim x→4 7− 12x+1 x−4

Answer

-67

12.R-21 §12.R source ↗

For the following exercises, use numerical evidence to determine whether the limit exists at x=a. If not, describe the behavior of the graph of the function at x=a.

f(x)= −2 x−4 ; a= 4

Answer

At x=4, the function has a vertical asymptote.

12.R-23 §12.R source ↗

For the following exercises, use numerical evidence to determine whether the limit exists at x=a. If not, describe the behavior of the graph of the function at x=a.

f(x)= −x x 2 −x−6 ; a= 3

Answer

At x=3, the function has a vertical asymptote.

12.R-25 §12.R source ↗

For the following exercises, use numerical evidence to determine whether the limit exists at x=a. If not, describe the behavior of the graph of the function at x=a.

f(x)= x −3 9−x ; a= 9

Answer

Removable discontinuity at a=9

12.R-27 §12.R source ↗

For the following exercises, determine where the given function f(x) is continuous. Where it is not continuous, state which conditions fail, and classify any discontinuities.

f(x)= x 2 −2x−15 x−5

Answer

Removable discontinuity at x=5

12.R-29 §12.R source ↗

For the following exercises, determine where the given function f(x) is continuous. Where it is not continuous, state which conditions fail, and classify any discontinuities.

f(x)= x 3 −125 2 x 2 −12x+10

Answer

Removable discontinuity at x=5, discontinuity at x=1

12.R-31 §12.R source ↗

For the following exercises, determine where the given function f(x) is continuous. Where it is not continuous, state which conditions fail, and classify any discontinuities.

f(x)= x+2 x 2 −3x−10

Answer

Removable discontinuity at x=-2, discontinuity at x=5

12.R-33 §12.R source ↗

For the following exercises, find the average rate of change f(x+h)−f(x) h .

f(x)=3x+2

Answer

3

12.R-35 §12.R source ↗

For the following exercises, find the average rate of change f(x+h)−f(x) h .

f(x)= 1 x+1

Answer

1 (x+ 1)(x+h+1)

12.R-37 §12.R source ↗

For the following exercises, find the average rate of change f(x+h)−f(x) h .

f(x)= e 2x

Answer

e2x+2h-e2x h

12.R-39 §12.R source ↗

For the following exercises, find the derivative of the function.

f(x)=5 x 2 −3x

Answer

10x-3

12.R-41 §12.R source ↗

For the following exercises, with the aid of a graphing utility, explain why the function is not differentiable everywhere on its domain. Specify the points where the function is not differentiable.

f(x)= x | x |

Answer

The function would not be differentiable at however, 0 is not in its domain. So it is differentiable everywhere in its domain.

12.T-1 §12.T source ↗

For the following exercises, use the graph of f in Figure 1.

Graph of a piecewise function with two segments. The first segment goes from negative infinity to (-1, 0), an open point, and the second segment goes from (-1, 3), an open point, to positive infinity. Figure 1

f(1)

Answer

3

12.T-3 §12.T source ↗

For the following exercises, use the graph of f in Figure 1.

Graph of a piecewise function with two segments. The first segment goes from negative infinity to (-1, 0), an open point, and the second segment goes from (-1, 3), an open point, to positive infinity. Figure 1

lim x→ −1 − f(x)

Answer

0

12.T-5 §12.T source ↗

For the following exercises, use the graph of f in Figure 1.

Graph of a piecewise function with two segments. The first segment goes from negative infinity to (-1, 0), an open point, and the second segment goes from (-1, 3), an open point, to positive infinity. Figure 1

lim x→−2 f(x)

Answer

−1

12.T-7 §12.T source ↗

For the following exercises, with the use of a graphing utility, use numerical or graphical evidence to determine the left- and right-hand limits of the function given as x approaches a. If the function has a limit as x approaches a, state it. If not, discuss why there is no limit

f(x)={ 1 x −3, if x≤2 x 3 +1,if x>2   a=2

Answer

lim x→ 2 − f(x)= − 5 2 a and lim x→ 2 + f(x)= 9 Thus, the limit of the function as x approaches 2 does not exist.

12.T-10 §12.T source ↗

For the following exercises, evaluate each limit using algebraic techniques.

lim h→0 ( h 2 +25 −5 h 2 )

Answer

-150

12.T-12 §12.T source ↗

For the following exercises, determine whether or not the given function f is continuous. If it is continuous, show why. If it is not continuous, state which conditions fail.

f(x)= x 2 −4

Answer

1

12.T-14 §12.T source ↗

For the following exercises, use the definition of a derivative to find the derivative of the given function at x=a.

f(x)= 3 5+2x

Answer

Removable discontinuity at x=3

12.T-16 §12.T source ↗

For the following exercises, use the definition of a derivative to find the derivative of the given function at x=a.

f(x)=2 x 2 +9x

Answer

f'(x)= - 3 2a32

12.T-18 §12.T source ↗

For the following exercises, with the aid of a graphing utility, explain why the function is not differentiable everywhere on its domain. Specify the points where the function is not differentiable.

f(x)= |x− 2|− |x+ 2|

Answer

Discontinuous at −2, 0, not differentiable at −2, 0, 2

12.T-20 §12.T source ↗

For the following exercises, explain the notation in words when the height of a projectile in feet, s, is a function of time t in seconds after launch and is given by the function s(t).

s(0)

Answer

Not differentiable at x=0 (no limit)

12.T-22 §12.T source ↗

For the following exercises, explain the notation in words when the height of a projectile in feet, s, is a function of time t in seconds after launch and is given by the function s(t).

s'(2)

Answer

The height of the projectile at t=2 Seconds

12.T-24 §12.T source ↗

For the following exercises, explain the notation in words when the height of a projectile in feet, s, is a function of time t in seconds after launch and is given by the function s(t).

s(t)=0

Answer

The average velocity from t=1 t=2

12.T-26 §12.T source ↗

For the following exercises, use technology to evaluate the limit.

lim x→0 tan 2 (x) 2x

Answer

13

12.T-28 §12.T source ↗

For the following exercises, use technology to evaluate the limit.

Evaluate the limit by hand.

lim x→1 f(x), where  f(x)={ 4x−7 x≠1 x 2 −4 x=1

At what value(s) of x is the function below discontinuous?

f(x)={ 4x−7x≠1 x 2 −4x=1

Answer

0

12.T-29 §12.T source ↗

For the following exercises, consider the function whose graph appears in Figure 3.

Graph of a positive parabola. Figure 3

Find the average rate of change of the function from x= 1 to x= 3.

Answer

2

12.T-30 §12.T source ↗

For the following exercises, consider the function whose graph appears in Figure 3.

Graph of a positive parabola. Figure 3

Find all values of x at which f'(x)=0.

Answer

x=1

12.T-32 §12.T source ↗

For the following exercises, consider the function whose graph appears in Figure 3.

Graph of a positive parabola. Figure 3

Find an equation of the tangent line to the graph of f the indicated point: f(x)= 3 x 2 − 2x− 6,   x= − 2

Answer

y=−14x−18

12.T-34 §12.T source ↗

For the following exercises, use the function f(x)= x ( 1−x ) 2 5 .

Explore the behavior of the graph of f(x) around x=1 by graphing the function on the following domains, [0.9, 1.1], [0.99, 1.01], [0.999, 1.001], and [0.9999, 1.0001]. Use this information to determine whether the function appears to be differentiable at x=1.

Answer

The graph is not differentiable at x=1 (cusp).

12.T-36 §12.T source ↗

For the following exercises, find the derivative of each of the functions using the definition: lim h→0 f(x+h)−f(x) h

f(x)=4 x 2 −7

Answer

f ' (x)=8x

12.T-38 §12.T source ↗

For the following exercises, find the derivative of each of the functions using the definition: lim h→0 f(x+h)−f(x) h

f(x)= 1 x+2

Answer

f ' (x)= − 1 ( 2+x ) 2

12.T-40 §12.T source ↗

For the following exercises, find the derivative of each of the functions using the definition: lim h→0 f(x+h)−f(x) h

f(x)=− x 3 +1

Answer

f ' (x)=−3 x 2

12.T-42 §12.T source ↗

For the following exercises, find the derivative of each of the functions using the definition: lim h→0 f(x+h)−f(x) h

f(x)= x−1

Answer

f'(x)= 1 2 x−1

End of the book.

Problems and answers are adapted from Precalculus 2e by Jay Abramson, OpenStax, and are used under the CC BY-NC-SA 4.0 licence. Access for free at https://openstax.org/books/precalculus-2e/pages/1-introduction-to-functions. Illustrations: Copyright Rice University, OpenStax, under CC BY-NC-SA 4.0 license. This adaptation is released under the same licence, is non-commercial, and is neither affiliated with nor endorsed by OpenStax or Rice University.