Given the intergral $\displaystyle \iint_S a \ dS$

where

$\displaystyle a = (x^2 + y^2 + z^2)xi + j + zk$

where $\displaystyle S$ is the sphere $\displaystyle x^2+y^2+z^2 = 2$

I need to:

a)Evaluate the surface integral directly

b)Use Gauss's theorem to evaluate the integral

I have looked through my notes and searched the web. I have found a few examples but they aren't the same as this question and i cant work out the differences.

Any pointers in the right direction would be helpful, because i understand the theory of surface integrals, but am struggling to mathematically apply it.

Thanks

Jez