Mathematical induction, polar coordinates and parametric equations. According to the relevant data of the old college entrance examination, the old college entrance examination liberal arts mathematics does not test mathematical induction, polar coordinates and parametric equations. The old college entrance examination is a 3+X scheme of arts and sciences, in which "3" means "Chinese, mathematics and foreign languages" and "X" means that students choose one of the two comprehensive subjects of arts and sciences as an examination subject according to their own wishes.