cos(π/6-a)=a,则sin(2π/3-a)=

问题描述:

cos(π/6-a)=a,则sin(2π/3-a)=

sin(2π/3-a)
=cos[π/2-(2π/3-a)]
=cos(a-π/6)
=cos(π/6-a)
=a