问题
选择题
已知tan(θ+
|
答案
由题意tan(θ+
)=π 4
=-3,解得tanθ=21+tanθ 1-tanθ
又sin2θ+sinθcosθ-2cos2θ=
=sin2θ+sinθcosθ-2cos2θ sin2θ+cos2θ
=tan2θ+tanθ-2 tan2θ+1
=4+2-2 4+1 4 5
故选D
已知tan(θ+
|
由题意tan(θ+
)=π 4
=-3,解得tanθ=21+tanθ 1-tanθ
又sin2θ+sinθcosθ-2cos2θ=
=sin2θ+sinθcosθ-2cos2θ sin2θ+cos2θ
=tan2θ+tanθ-2 tan2θ+1
=4+2-2 4+1 4 5
故选D