If a and b are positive constants, evaluate the following integrals:

The integral from 0 to infinity, of (e^-ax sin bx)/x dx

ta said answer was: pie/2 - tan^-1 (a/b), but book says tan^-1(b/a), so which? and how?

The integral from 0 to infinity, of (e^-ax - e^-bx)/x dx

ta said answer was ln(a/b), but book says log b/a, so which? and how?

thanks!