AskiitianExpert Shine
Last Activity: 16 Years ago
Hi
VOLUME OF A SPHERE( its formula can be derived using integral calculus)
At any given x, the incremental volume (δV) is given by the product of the cross-sectional area of the disk at x and its thickness (δx):

The total volume is the summation of all incremental volumes:

In the limit as δx approaches zero this becomes:

At any given x, a right-angled triangle connects x, y and r to the origin, whence it follows from Pythagorean theorem that:

Thus, substituting y with a function of x gives:

This can now be evaluated:
![\!V = \pi \left[r^2x - \frac{x^3}{3} \right]_{x=0}^{x=r} = \pi \left(r^3 - \frac{r^3}{3} \right) = \frac{2}{3}\pi r^3.](http://upload.wikimedia.org/math/d/a/0/da0ec8ffc1583ad523f77280e451c6cf.png)
This volume as described is for a hemisphere. Doubling it gives the volume of a sphere as:
