Calculus
posted by Jess .
Can someone please tell me how to derive V=4/3pi(r)^3 to get x^2+y^2=r^2?

You can derive the formula for the volume of a sphere by rotating the circle
x^2 + y^2 = r^2 about the x axis by taking the
integral of pi(r^2  x^2)dx from r to +r
Is this what you meant?