Question

why is an area of sphere is 4*pi*r^2?? can you guys prove?

Answer 1

\[da=\int\limits_{\theta =0}^{\pi}\int\limits_{\phi =0}^{ 2\pi}r \sin \theta d \theta d \phi\]

Answer 2

that will be r^2 in stead of r

Answer 3

i think u have understood..