已知sinθ+cosθ=4/3(0

问题描述:

已知sinθ+cosθ=4/3(0

(sinθ+cosθ)²=16/9
sinθ²+cosθ²+2sinθcosθ=16/9
2sinθcosθ=7/9
sinθ-cosθ=根号下(sinθ-cosθ)²=根号下(1-7/9)=(根号2)/3 (π/4