## Aenn88 2 years ago Consider the solid obtained by rotating the region bounded by the given curves about the y-axis. Find the volume of this solid. y^2=4x x=y I don't know how to start!

1. cwrw238

the diagram looks something like this

2. ZeHanz

Always begin with a drawing, to see what is going on:

3. cwrw238

|dw:1359323354480:dw|

4. cwrw238

very rough of course!!!!

5. ZeHanz

@cwrw238: Geogebra is your friend ;)

6. ZeHanz

@Aenn88: do you know the Shell method?

7. cwrw238

geogebra? i must try that

8. Aenn88

using cylindrical shells? i somewhat understand it in watching videos but I have a hard time applying it to another problem. i will use geogebra in the future! :)

9. Aenn88

@ZeHanz

10. ZeHanz

See geogebra.org. First , remember if y²=4x then y=√(4x). Here r is x, and h is the length of the vertical difference of the two graphs: Cylindrical shells:$\int\limits_{0}^{4}2\pi r hdr=\int\limits_{0}^{4}2\pi x(\sqrt{4x}-x)dx$

11. Aenn88

ok that makes sense..thank you