cosθ-sinθ=-√3/2
(cosθ-sinθ)^2 =cosθ^2 + sinθ^2 -2sinθcosθ =1-2sinθcosθ =3/4
2sinθcosθ=1/4
sinθcosθ=1/8
(sinθ+cosθ)^2 = 1+2sinθcosθ=5/4
sinθ+cosθ =+- √5/2
cosθ-sinθ=-√3/2
(cosθ-sinθ)^2 =cosθ^2 + sinθ^2 -2sinθcosθ =1-2sinθcosθ =3/4
2sinθcosθ=1/4
sinθcosθ=1/8
(sinθ+cosθ)^2 = 1+2sinθcosθ=5/4
sinθ+cosθ =+- √5/2