∫1sin(x−a)sin(x−b)dx=
1sin(a−b)logsin(x−a)sin(x−b)+C
−1sin(a−b)logsin(x−a)sin(x−b)+C
logsin(x−a)sin(x−b)+C
We have,
∫1sin(x−a)sin(x−b)dx=1sin(b−a)∫sin{(x−a)−(x−b)}sin(x−a)sin(x−b)dx=1sin(b−a)∫{cot(x−b)−cot(x−a)}dx=1sin(b−a){logsin(x−b)−logsin(x−a)}+C=1sin(b−a)logsin(x−b)sin(x−a)+C=1sin(a−b)logsin(x−a)sin(x−b)+C