cos^2(π+α)+sin(-α)cos(2π+α)tan(-π-α)

题目

cos^2(π+α)+sin(-α)cos(2π+α)tan(-π-α)
今天就要

答案

sin²（α+π）.cos（π+α）.cos(-α-2π）/tan(π+α）.sin³(π/2+α).sin(-α-2π)=sin²α*(-cosα)*cosα/tanα*(-cos³α)sinα=-sin²αcos²α/(-sin²αcos²α)=1