sin(x/2)﹣ cos(x/2)= 更号2

问题描述:

sin(x/2)﹣ cos(x/2)= 更号2

[sin(x/2)-cos(x/2)]²=sin²(x/2)+cos²(x/2)-2sin(x/2)cos(x/2)=1-sin(2*x/2)=2
sinx=-1
x=3π/2+2kπ,k∈整数