cos(π/3-2x)=cos(π/3)sin(2x+π/6))=sin(π/6)因为cos(π/3)=sin(π/6)所以cos(π/3-2x)=sin(2x+π/6)另一种解法:cos(π/3-2x) 根据公式 cosx=sin(π/2-x) 得=sin[π/2-(π/3-2x)]=sin[（π/2-π/3）+2x]=sin(2x+...