1) ∫cos 5x+cos 4x1-2 cos 3xdx
=∫2cos(9x/2).cos(x/2)1-2{2cos2(3x/2)-1}dx
=∫2cos(9x/2).cos(x/2).cos(3x/2)3cos(3x/2)-4cos3(3x/2)dx
=∫2cos(9x/2).cos(x/2).cos(3x/2)-cos(9x/2)dx
= - ∫ 2cos(3x/2)cos(x/2) dx
= - ∫ cos(2x)+cos(x)dx
= -sin(2x)2-sin(x)+c
- Harsh Bharvada Thanx.......can u help me wit d other 2 also???
Upvote·0· Reply ·2013-08-08 00:25:49