Volume of Solid Revolving Region Bounded by x=y^2, x=4 About x=5

[Blonde1551]

Homework Statement

Find volume of the solid generated by revolving the region bounded by x = y^2, x=4
about the line x = 5

Homework Equations

the washer method from c to d ∏∫ R(y)² - r(y)²

The Attempt at a Solution

I set r(y) = 1 and R(y)= y^2

and got the integral from 0 to 2 of ∏∫(y^2)^2-(1)^2

I got an answer of 16.96 but i know this is wrong because the back of the book gives a different answer. Please tell me where I went wrong.

 

[SammyS]

Homework Statement

Find volume of the solid generated by revolving the region bounded by x = y^2, x=4
about the line x = 5

Homework Equations

the washer method from c to d ∏∫ R(y)² - r(y)²

The Attempt at a Solution

I set r(y) = 1 and R(y)= y^2

and got the integral from 0 to 2 of ∏∫(y^2)^2-(1)^2

I got an answer of 16.96 but i know this is wrong because the back of the book gives a different answer. Please tell me where I went wrong.

Think about what the washer method involves -- why it's called the "washer" method.

What do r(y) and R(y) represent?