Question

(1-cos x)(1+cos x ) ctg 2x упростить выражение

Answer 1

(1 - Cosx)(1 + Cosx)Ctg²x = (1 - Cos²x)Ctg²x = Sin²x * Ctg²x =
= $Sin ^{2}x* frac{Cos ^{2}x }{Sin ^{2} x} =Cos ^{2}x$