若sin(α-π/3),则cos﹙α+π/6﹚=

问题描述:

若sin(α-π/3),则cos﹙α+π/6﹚=

sin(α-π/3)=-sin(π/2-(π/6+α))=-cos(α+π/6)sin(α-π/3)=3/5结果应该是-3/5