Докажите тождество(Sint+cost)^2-1 / ctgt-sint*cost=2tg^2t

Question

Докажите тождество

(Sint+cost)^2-1 / ctgt-sint*cost=2tg^2t

Answer 1

(Sint+cost)^2-1 / ctgt-sint*cost=(sin^2t+2sint*cost+cos^2t-1*)sint/cost(1-sin^2t)=

2sin^2t/cos^2t=2tg^2t