三角函数的诱导公式题解答化简1.cos(α-π/2)/sin(5π/2+α)×sin(α-2π)×cos(2π-α)2.cos^2(-α)-tan(360°+α)/sin(-α)

Question

三角函数的诱导公式题解答
化简
1.cos(α-π/2)/sin(5π/2+α)×sin(α-2π)×cos(2π-α)
2.cos^2(-α)- tan(360°+α)/sin(-α)

Answer 1

1.原式=(sina/cosa)乘以 sina 乘以cosa
=sina^2
2.原式=cos^2(a)-tana/sina
=cos^2(a)-1/cosa
=(cos^3-1)/cosa
补充：cos(α-π/2)=sina sin(5π/2+α)=sin(π/2-a)=cosa sin(α-2π)=sina
cos(2π--α)=)=cos(-α)=cosa
a表示α 不好意思,还不知道 α怎么打出