I need help finding the volume of a solid by rotating, one graph is y=0.5x^2 and the other is y=x. The region bounded by the two is rotated around the line x=3, i'm confused as to how to do this, any help would be nice.

Question

amistre64 · Answer

what parts are not confusing to you ... lets start there

amistre64 · Answer

you thinking shells or washers?

anonymous · Answer

I was thinking washer, correct?

amistre64 · Answer

either way, whatevers simplest for you.

amistre64 · Answer

what are our points of intersection? 0,0 and what else?

anonymous · Answer

0,0 and 2,2

amistre64 · Answer

so if we do washers, whats our formula for area of a washer?

amistre64 · Answer

|dw:1431727407585:dw|

anonymous · Answer

$$\int\limits_{0}^{2} \Pi [(f(x)^2 - (g(x)^2]$$

amistre64 · Answer

well, R^2 and r^2  they may not be singular functions

amistre64 · Answer

|dw:1431727575628:dw|

R=3-y
r=3-sqrt(2y)