# Math Help - surface integrals

1. ## surface integrals

Evaluate the surface integrals.

a) f(x,y,z)=(x^2+y^2)z; sigma is the portion of the sphere x^2+y^2+z^2=4 above the plane z=1

b) f(x,y,z)=x^2+y^2; sigma is the surface of the sphere x^2+y^2+z^2=a^2

2. In the attachment I walk you through the first one --I'll leave the second for you