若tanθ=1/3,则cos²θ+sinθcosθ的值是?

来源：学生作业学帮网编辑：学帮网时间：2024/05/30 22:29:32

若tanθ=1/3,
则cos²θ+sinθcosθ
=(cos²θ+sinθcosθ)/(sin²θ+cos²θ)
=[(cos²θ/cos²θ)+(sinθcosθ/cos²θ)]/[(sin²θ/cos²θ)+(cos²θ/cos²θ)]
=(1+tanθ)/(tan²θ+1)
=(1+1/3)/(1/9+1)
=6/5