请问什么是椭圆、双曲线、抛物线？如果把他们看作是满足一个解析表达式的曲线，那么自然就只能用解析几何的做。
Germinal Pierre Dandelin (April 12, 1794 - February 15, 1847) was a mathematician, soldier, and professor of engineering. He was born near Paris to a French father and Belgian mother, studying first at Ghen采用丹德林双球公式。
采用丹德林双球公式。