已知sinθ+cosθ=1-√3/2(0 1-√3/2是分子是1-根號3,分母是2

已知sinθ+cosθ=1-√3/2(0 1-√3/2是分子是1-根號3,分母是2

(sinθ+cosθ)^2=(2-√3)/2
1+2sinθcosθ=(2-√3)/2
1+sin2θ=(2-√3)/2
sin2θ=-√3/2
0