(cot^2t+1)(sin^2t+1)=cot^2t+2
cot^2t *sin^2t + cot^2t + sin^2t + 1 = cot^2t +2
( cott = cost/sint, and cos^2t + sin^2t = 1 )
cos^2t/sin^2t*sin^2t +cot^2t +sin^2t + 1 = cot^2t + 2
sin^2t + cot^2t + cos^2t + 1 = cot^2t +2
1+ cot^2t + 1 = cot^2t +2
cot^2t + 2 = cot^2 + 2