Surface area of sphere above xy-plane within cylinder

[naspek]

Find the surface area of that portion of the sphere x^2 + y^2 + z^2 = a^2 that is above xy-plane and within the cylinder x^2 + y^2 = b^2 , 0 < b < a

Solution.. i try to find fx and fy..

http://imageshack.us/f/594/33049204.jpg/"

how am i going to proceed?

 

[ehild]

It would be very simple with spherical polar coordinates.

ehild