我们知道,下列不等式:x~2+y~2<1、x~2/a~2+y~2/b<1(a>b>0)、y~2<2px表示的区域分别是圆的内部、椭圆的内部、抛物线的内部.有关圆锥曲线的问题,我们常常是从定义和性质出发来考虑的。至于圆锥曲线的内部区域往往不被重视,其实圆锥曲线的内部在数学中有许多重要的作用. We know that the following inequalities: x~2+y~2<1, x~2/a~2+y~2/b<1 (a>b>0), y~2<2px The inner part of the ellipse, the inner part of the ellipse, the inner part of the parabola. Concerning the question of the conic section, we often consider it from the definition and the nature. As for the internal region of the conic section is often not taken seriously, in fact, the interior of the conic section has many important roles in mathematics.