hiiiii
Well there is a famous result which is as follows ...
0
/2 sin
mx.cos
nx.dx = (G(m+1/2)G(n+1/2))/2.G((m+n+2)/2)
where G is gamma function and it satisfies the following properties ..
(i) G(1) = 1 and G(n+1) = n.G(n)
(ii) G(n+1) = n! if n is a natural number
(iii) G(1/2) =

Let me give you some advice ... whenever u see limit between 0 to

/2 and sinx , cosx terms ... do try to use this formula .. it is very useful and shud be learnt by heart ..
cheers