# [SOLVED] Volume of solid obtained by rotsting the bounded region

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• Feb 11th 2010, 04:56 PM
yzobel
[SOLVED] Volume of solid obtained by rotsting the bounded region
Find the volume of the solid obtained by rotating the bounded region in the first quadrant enclosed by the graphs of y=x2, x=y^4 about the x-axis.

Here's what i did:
r1=1+y
r2=sqrt(y)-y^4

2pi 0--1 (1+y)(sqrt(y)-y^4)dy

I integrated this and got 7pi/5 which is incorrect. Are my radii and formula correct? If not, could someone please correct it? Thanks
• Feb 11th 2010, 05:01 PM
skeeter
Quote:

Originally Posted by yzobel
Find the volume of the solid obtained by rotating the bounded region in the first quadrant enclosed by the graphs of y=x2, x=y^4 about the x-axis.

Here's what i did:
r1=1+y
r2=sqrt(y)-y^4

2pi 0--1 (1+y)(sqrt(y)-y^4)dy

I integrated this and got 7pi/5 which is incorrect. Are my radii and formula correct? If not, could someone please correct it? Thanks

I assume it's $y = x^2$

washers w/r to x ...

$V = \pi \int_0^1 \sqrt{x} - x^4 \, dx$