sin(a+π/6)=+-3/5sina=sin(a+π/6-π/6)=sin(a+π/6)cosπ/6-sinπ/6cos(a+π/6)sin(a+π/6)=3/5,sina=3/5x√3/2-1/2x(-4/5)=(3√3+4)/10sin(a+π/6)=-3/5,sina=-3/5x√3/2-1/2x(-4/5)=(-3√3+4)/10