Double Integral Surface Area of Spherical Ball

[Philosophaie]

Homework Statement

Double Integral Surface Area of Spherical Ball radius

Homework Equations

$\int_S d\vec{S} = 4*\pi*a^2$

The Attempt at a Solution

$\int\int_0^a f(r,?) dr d? = 4*\pi*a^2$

 

[LCKurtz]

Homework Statement

Double Integral Surface Area of Spherical Ball radius

Homework Equations

$\int_S d\vec{S} = 4*\pi*a^2$

The Attempt at a Solution

$\int\int_0^a f(r,?) dr d? = 4*\pi*a^2$

What is the dS element in spherical coordinates?

 

[Philosophaie]

$dS = r^2*sin\phi*d\theta*d\phi$

I can take it from here!

 

[LCKurtz]

Good. Remember the only two variables are $\theta$ and $\phi$. The radius is constant.