Question

sin(3π/2-x)ctg(5π/2+x)

Answer 1

sin(3π/2-x)ctg(5π/2+x)=-cosx(-tgx)=

cosx *sinx/cosx=sinx

Answer 2

sin(3π/2 - x) · ctg(5π/2 + x) =

= - cosx ·(- tgx) = cosx · (sinx/cosx) = sinx