数学题三角函数已知2sin(3π+θ)=cos(π+θ),求2sin^2 θ+3sinθcosθ-cos^2 θ_数学解答

数学题三角函数
已知2sin(3π+θ)=cos(π+θ),求2sin^2 θ+3sinθcosθ-cos^2 θ

人气：290 ℃　时间：2020-04-10 03:13:21

解答

2sin(3π+θ)=cos(π+θ)2sinθ=cosθtanθ=1/22sin^2 θ+3sinθcosθ-cos^2 θ2sin^2 θ+3sinθcosθ-cos^2 θ___________________________=____________________________=1...