sin(a-π/6)=1/3cos(a-π/6)=√[1-sin^2(a-π/6)]=√(1-1/9)=2√2/3sinacosπ/6-cosasinπ/6/2sina-1/2cosa=1/3cosα=(a-π/6+π/6)=cos(a-π/6)cosπ/6-sin(a-π/6)sinπ/6=(2√2/3)*(√3/2)-(1/3)*(1/2)=(2√6-1)/...