三角函数诱导公式已知sin(π+α)= -1/2,计算1.sin(5π-α)2.sin(π/2+α)3.cos(α- 3π/2)4.tan(π/2-α)
问题描述：
三角函数诱导公式
已知sin(π+α)= -1/2,计算
1.sin(5π-α)
2.sin(π/2+α)
3.cos(α- 3π/2)
4.tan(π/2-α)
答
sin(π+α)= -1/2-sinα= -1/2sinα= 1/21.sin(5π-α)=sin(π-α)=sinα=1/22.sin(π/2+α)=sin( π- π/2-α)=sin( π/2-α)=cosα=√(1-sin²a)=√3/23.cos(α- 3π/2)=cos(α- 3π/2+2π)=cos(α+π/2)=cos(...