i ll manage to fix it i think but only I need to get the primitive of sin x.If an exact value can be found for that definite integral, I suspect you should make a contour integral in the complex plane in order to crack it.
What's wrong with one step IBP?Hint: try to decompose the integral into two integrals. one should have limits of integration from 0 to pi/2
exploit symmetry and manipulate the limits of integration to solve the problem. these identities might also help: sin(x) = sin(pi - x), 2sin(x)cos(x) = sin(2x).
[tex]Yes, I agree it's a series of tricks. I just solved it yesterday and was amazed at the elegance of the solution. Dick's hint in the other thread proves to be very helpful.