# Thread: Integrals - Volume AGAIN

1. ## Integrals - Volume AGAIN

Hello.
Question:
Show that y=2sqrt(1-x^2) and y=sqrt(1-x^2) intersect at (1,0)and (-1,0). Find the volume of the solid when the enclosed region is rotated.
A) about the y-axis.
I already calculated the x-axis and I got it right.

My attempt:
I don't know how to use the program and insert the cool f's and stuff.
so I will skip that bit
pi(-(2)^3/12 +2) - pi(-(1)/5) + 1)
pi(-(4/3) - pi(4/5)

My answer is way wrong please help me.
Thanks

2. Originally Posted by Awsom Guy
I don't know how to use the program and insert the cool f's and stuff.
so
... so, explain your steps in words, at least. E.g. I said, 2 pi times the int from zero to 2 of the following...

Otherwise we can't see where you took a wrong turn and we'll end up spoiling your fun