2sinθcosθ+2sinθ-cosθ-1 = 0 0
问题描述:
2sinθcosθ+2sinθ-cosθ-1 = 0 0
答
2sinθcosθ+2sinθ-cosθ-1
=2sinθ(cosθ+1)-(cosθ+1)
=(cosθ+1)(2sinθ-1)=0
cosθ=-1 or sinθ=1/2
θ=π or π /6 or 2π /3