I= ∫ cotxlogsinxdx ( 1 )
Consider logsinx=t
Differentiating both sides,
1 sinx ×cosxdx=dt cotxdx=dt
Substitute in equation ( 1 )
I= ∫ cotxlogsinxdx I= ∫ tdt I=[ t 1+1 1+1 ]+C I= t 2 2 +C I= 1 2 t 2 +C ( 2 )
Substitute t=logsinx in equation ( 2 )
I= 1 2 ( logsinx ) 2 +C
Thus, the integral is I= 1 2 ( logsinx ) 2 +C