# volume of sphere

• Apr 13th 2009, 12:31 PM
metlx
volume of sphere
how to get to the volume of sphere with radius r using the integrals..

that's what i tried..

$\int \Pi r^2 dr = \frac{\Pi r^3}{3}$

I'm missing 4 :P
• Apr 13th 2009, 12:54 PM
Jhevon
Quote:

Originally Posted by metlx
how to get to the volume of sphere with radius r using the integrals..

that's what i tried..

$\int \Pi r^2 dr = \frac{\Pi r^3}{3}$

I'm missing 4 :P

use volumes of revolutions. rotate a semi circle of radius r in the upper half-plane, centered at the origin about the x-axis. use the disk method