Sin^2t(1+ctg^2t)-cos^2t=sin^2t

Question

Sin^2t(1+ctg^2t)-cos^2t=sin^2t

Answer 1

Делаем по действиям:
1)1 + Ctg²t = 1/Sin²t
2) Sin²t * 1/Sin²t = 1
3) 1 - Sin²t = Cos²t