∫cotx cot(2400−x) cot(2400+x)dx
−13log (sin3x)+c
13log (sin3x)
13log (sin3x)+C
13log (cosec3x)
We know that
tanxtan240∘−xtan240∘+x=tan3x∫cotxcot(240−x)cot(240+x)dx=∫cot3xdx=13log(sin3x)+C