Question

化简cos(α-π/2)/sin(α+5π/2)*sin(α-2π)*cos(2π-α)，因为我刚学，所以要具体点的过程哦～

额……答案是sinα的平方

Answer 1

解：原式=(cos(-(π/2-α))/sin(2π+π/2+α))*sin(-(2π-α))*cos(2π-α)
=(cos(π/2-α)/sin(π/2+α))*(-sin(2π-α))*cosα
=(sinα/cosα)*sinα*cosα
=sin²α。

Answer 2

我打了图片，自己看吧