A:①②③
B:④⑤⑥
C:⑦⑧⑨
D:①③⑤
This is only a solution that can be adopted to solve the problem , so you have to find a better way.
在极坐标系中,直线 ρcos(θ+π3)=1 与曲线 ρ=r ( r>0 )相切,求 r 的值.