参数方程是理科选修内容.圆和椭圆的参数方程虽然要求不高,但参数由于有直观的几何意义以及大量三角公式的支持,在解决圆和椭圆上动点求最值、求范围类问题时价值较大.并且由于引入参数还可以使得需要引入的参数变少,处理起来更简便些. The parametric equation is the content of science. Although the parametric equations of the circle and the ellipse are not very demanding, the parameters have intuitive geometric meaning and support of a large number of trigonometric formulas. When solving the problems of finding the optimal value and the range of the moving points on circles and ellipses The value is relatively large, and the introduction of parameters can also reduce the number of parameters that need to be introduced, making it easier to handle.