计算sin(α-π/4)+cos(α+π/4)的值.
问题描述:
计算sin(α-π/4)+cos(α+π/4)的值.
答
cos(α+π/4)=cos(a-π/4+π/2)
=-sin(a-π/4)
所以sin(α-π/4)+cos(α+π/4)=0