The correct option is B cosec(b−a)ln∣∣∣sin(x−b)sin(x−a)∣∣∣+C
Let
I=∫dxsin(x−a)sin(x−b)
⇒I=1sin(b−a)∫sin((x−a)−(x−b))dxsin(x−a)sin(x−b)
⇒I=cosec(b−a)[∫cot(x−b)dx−∫cot(x−a)dx]
⇒I=cosec(b−a)[ln|sin(x−b)|−ln|sin(x−a)|]+C
∴I=cosec(b−a)ln∣∣∣sin(x−b)sin(x−a)∣∣∣+C