在极坐标系中,与圆ρ=4sinθ相切的一条直线方程为( )A.ρsinθ=2 B.ρcosθ=2C.ρcosθ=4 D.ρcosθ=-4 答案:思路解析:如图,⊙C的极坐标方程为ρ=4sinθ,CO⊥Ox,OA为直径,|OA|=4,l和圆相切,l交极轴于B(2,0),点P(ρ,θ)为l上任意一点,则有cosθ=,得ρcosθ=2.答案:B"Do you want to have a school trip?" "______."
[ ]A. Yes, you do B. No, I do C. Yes, you don't D. No, I don't