Question

Question #1381d

Answer 1

`RHS= (sin 5x + sin 7x)/(Cos 5x - cos 7x)`

`= (2sin( (5x+7x)/2) cos ((7x-5x)/2))/ (2sin( (5x+7x)/2) sin ((7x-5x)/2))`

`= (sin( 6x) cos (x))/ (sin( 6x) sin x)=cotx=LHS`