168k views
18 votes
Find the average rate of change of the function between the given values of x.

y = -5x - x^2 between x = -5 and x = 7

User Marshally
by
4.0k points

1 Answer

5 votes

Answer:

Use integrals to find the area between the curves.

32

3

Solve for the first variable in one of the equations, then substitute the result into the other equation.

Point Form:

(

0

,

0

)

,

(

4

,

4

)

Equation Form:

x

=

0

,

y

=

0

x

=

4

,

y

=

4

To find the volume of the solid, first define the area of each slice then integrate across the range. The area of each slice is the area of a circle with radius

f

(

x

)

and

A

=

π

r

2

.

V

=

π

4

0

(

f

(

x

)

)

2

(

g

(

x

)

)

2

d

x

where

f

(

x

)

=

x

2

+

5

x

and

g

(

x

)

=

x

Simplify the integrand.

Tap for more steps...

V

=

x

4

10

x

3

+

24

x

2

Split the single integral into multiple integrals.

V

=

π

(

4

0

x

4

d

x

+

4

0

10

x

3

d

x

+

4

0

24

x

2

d

x

)

By the Power Rule, the integral of

x

4

with respect to

x

is

1

5

x

5

.

V

=

π

(

1

5

x

5

]

4

0

+

4

0

10

x

3

d

x

+

4

0

24

x

2

d

x

)

Combine

1

5

and

x

5

.

V

=

π

(

x

5

5

]

4

0

+

4

0

10

x

3

d

x

+

4

0

24

x

2

d

x

)

Since

10

is constant with respect to

x

, move

10

out of the integral.

V

=

π

(

x

5

5

]

4

0

10

4

0

x

3

d

x

+

4

0

24

x

2

d

x

)

By the Power Rule, the integral of

x

3

with respect to

x

is

1

4

x

4

.

V

=

π

(

x

5

5

]

4

0

10

(

1

4

x

4

]

4

0

)

+

4

0

24

x

2

d

x

)

Combine

1

4

and

x

4

.

V

=

π

(

x

5

5

]

4

0

10

(

x

4

4

]

4

0

)

+

4

0

24

x

2

d

x

)

Since

24

is constant with respect to

x

, move

24

out of the integral.

V

=

π

(

x

5

5

]

4

0

10

(

x

4

4

]

4

0

)

+

24

4

0

x

2

d

x

)

By the Power Rule, the integral of

x

2

with respect to

x

is

1

3

x

3

.

V

=

π

(

x

5

5

]

4

0

10

(

x

4

4

]

4

0

)

+

24

(

1

3

x

3

]

4

0

)

)

Simplify the answer.

Tap for more steps...

V

=

384

π

5

The result can be shown in multiple forms.

Exact Form:

V

=

384

π

5

Decimal Form:

V

=

241.27431579

image of graph

To find the volume of the solid, first define the area of each slice then integrate across the range. The area of each slice is the area of a circle with radius

f

(

x

)

and

A

=

π

r

2

.

V

=

π

4

0

(

f

(

x

)

)

2

(

g

(

x

)

)

2

d

x

where

f

(

x

)

=

x

2

+

5

x

and

g

(

x

)

=

x

Simplify the integrand.

Tap for more steps...

V

=

x

4

10

x

3

+

24

x

2

Split the single integral into multiple integrals.

V

=

π

(

4

0

x

4

d

x

+

4

0

10

x

3

d

x

+

4

0

24

x

2

d

x

)

By the Power Rule, the integral of

x

4

with respect to

x

is

1

5

x

5

.

V

=

π

(

1

5

x

5

]

4

0

+

4

0

10

x

3

d

x

+

4

0

24

x

2

d

x

)

Combine

1

5

and

x

5

.

V

=

π

(

x

5

5

]

4

0

+

4

0

10

x

3

d

x

+

4

0

24

x

2

d

x

)

Since

10

is constant with respect to

x

, move

10

out of the integral.

V

=

π

(

x

5

5

]

4

0

10

4

0

x

3

d

x

+

4

0

24

x

2

d

x

)

By the Power Rule, the integral of

x

3

with respect to

x

is

1

4

x

4

.

V

=

π

(

x

5

5

]

4

0

10

(

1

4

x

4

]

4

0

)

+

4

0

24

x

2

d

x

)

Combine

1

4

and

x

4

.

V

=

π

(

x

5

5

]

4

0

10

(

x

4

4

]

4

0

)

+

4

0

24

x

2

d

x

)

Since

24

is constant with respect to

x

, move

24

out of the integral.

V

=

π

(

x

5

5

]

4

0

10

(

x

4

4

]

4

0

)

+

24

4

0

x

2

d

x

)

By the Power Rule, the integral of

x

2

with respect to

x

is

1

3

x

3

.

V

=

π

(

x

5

5

]

4

0

10

(

x

4

4

]

4

0

)

+

24

(

1

3

x

3

]

4

0

)

)

Simplify the answer.

Tap for more steps...

V

=

384

π

5

The result can be shown in multiple forms.

Exact Form:

V

=

384

π

5

Decimal Form:

V

=

241.27431579

y

=

3

x

+

4

,

[

2

,

3

]

y

=

3

x

2

,

(

0

,

4

)

y

=

x

,

[

1

,

4

]

Explanation:

User Khaloymes
by
4.0k points