Try this.. tan(x)=sin(x)/cos(x) and cot(x) = cos(x)/sin(x) add them both you get c^2+s^2/c*s = 1/c*s

then it would become integral between 0 and pi/2 --> ln (1/cos(x)*sin*(x)) dx ...

now you know sin(2x)=2sin(x)cos(x)

see what you get form here...