# volume of the rotating body rotation curve

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• Dec 13th 2010, 07:53 AM
snopy
volume of the rotating body rotation curve
i big idiot i couldn´t count this task ....Could anyone help me please?

y = sinx
x = 0
x = π around the x axis

http://www.sdilej.eu/pics/9ee44f5f2f1c9 ... c915dc.jpg

outcome is 1/2 Π^2
• Dec 13th 2010, 07:58 AM
adkinsjr
So basically you don't know how to evaluate: $\pi\int_0^{\pi}sin^2(x)dx$ right? You have to use a trig identity.

integral of sine squared

So you should obtain $\pi\left[\frac{x}{2}-\frac{1}{4}sin(2x)\right]_0^{\pi}=\frac{\pi^2}{2}$