化简 1.sin(α-2π)sin(α+π)-2cos(α-π/2)sin(α-π)-cos²(π/2+α)sin²（α-π/2）2.————————————cos（α-3π）sin（3π/2+α）第二个是 cos（α-3π）sin（3π/2+α）分之 sin²（α-π/2）

化简sin(α+β)+sin(α-β)+2sinαsin(3π/2-β)= 化简sin^2(α-π/6)+sin^2(α+π/6)-sin^2α 化简sin^2α+sin^2β+2sinαsinβcos(α+β) 化简sin(α+β)-2sinαsinβ/2sinαsinβ+cos(α+β) 1.证明 cos(α-π/2)=sinα sin（α－π/2)=﹣sinαcos(α-π/2)=sinαsin（α－π/2)=﹣sinα 化简sin(-π/2-α)sin(πα)cos(-α-π)/cos(π-α)sin(3π α) 化简 {sin(π+α)cos(α-2π)tan9π/4}/sin(-α)sin(7π/2+α)过程 化简1－sin[α－2π]sin[π＋α]－2sin²[－α]. 化简sin²α-2sinαcosα+1 化简:sin(2π-α)cos(π+α)cos(11π/2-α)/cos(π-α)sin(3π-α)sin(-π-α)sin(9π/2+α) 化简sin(30+α)-sin(30-α) 2sin(α+π/3）=sinα+______ 为什么sin(2π-α)=-sinα? sin(kπ+α)化简 化简:(sinα-cosα)^2+sin4α/2cos2α 化简:sin^2x+sin^2(x+2π/3)+sin^2(x-2π/3) 化简 sin(π+α)+sin(2π+α)+sin(3π+α)+……+sin(kπ+α) k属于Z sin（α+β）-2sinαcosβ/2sinαsinβ+cos（α+β）化简 化简：sin(α+β)-2sinαcosβ/2sinαsinβ+cos(α+β)