Is this correct?

1. Oct 25, 2004

pt176900

I am attempting to solve a physics problem, and in the process am getting tripped up by an integral:

integrate from 0 to pi (sin(theta)cos(theta) d_theta)

sorry, I don't know how to use the symbols =/

at any rate, I substitute U for sin theta, du is cos theta, and integrate and of course I get sin^2(theta)/2 which of course equals 1 - cos 2(theta), evaluated from zero to pi, which gives me an answer of zero.

In the context (potential on the surface of a sphere), this doesn't make any sense - so obviously my math must be wrong somewhere. if someone can point it out, then i'd be much obliged.

Thanks

2. Oct 25, 2004

Tom Mattson

Staff Emeritus
You didn't make any mistake evaluating the integral, so if you think your answer is wrong, then it's got to be in the integral itself. Can you state the full problem here?