Evaluate $\iint_s F\cdot n \,ds$ without using the divergence theorem given $F(x,y,z)=(x,y,z)$ and S is the surface of the solid $W$, where $W=\{{(x,y,z)\in R^3 | x^2+y^2\le 1 \,and\, x^2+y^2+z^2\le4}$}, with the normal vector $n$ exterior.
Ans: $4\pi(8-3\sqrt 3 )$
Well, I'm kind lost in here. I think I have to separate the solid in 3 surfaces, but I don't know what else.