已知sin (π/6-x) =3/5,则cos(x+π/3)

问题描述:

已知sin (π/6-x) =3/5,则cos(x+π/3)
三角函数快忘完了。

cos(x π/3)=cos(π/2-(-x π/6))=sin (π/6-x) =3/5