Remember that polar coordinates are about replacing x and y as coordinates for a point on a plane by instead r, r and theta,which is the angle measured counterclockwise from the positive x-axis.
极坐标是关于r，θ的,用r，θ代替平面上一点的x，y坐标，是从原点到那一点的距离，，which，is，the，distance，from，the，origin，to，a，point，θ是由x轴逆时针旋转,而得到的夹角。