∫( 1/sin(x)*1/sin^2(x)dx
=[-cot(x)/sin(x)]-∫{cot(x)*cos(x)/sin^2(x)}dx
=-cot(x)/sin(x)-∫cos^2(x)/sin^3(x)dx
=-cot(x)/sin(x)-∫1/sin^3(x)dx+∫1/sin(x)dx