Wolfram Book 之圆锥曲线相关的轨迹问题

例 1

设该椭圆的弦的两个端点分别为 A(x1,y1)、B(x2,y2),根据已知条件有

Mathematica 代码:

Solve[{x1^2/25 + y1^2/75 == 1,

x2^2/25 + y2^2/75 == 1, (y2 – y1)/(x2 – x1) == 3, x1 + x2 == 2 x, y1 + y2 == 2 y}, y, {x1, x2, y1, y2}, Reals]

例 2

Mathematica 代码:

Eliminate[{x1^2/9 + y1^2/4 == 1,

x2^2/9 + y2^2/4 == 1, (y – 0)/(x – 1) == (y2 – y1)/(x2 – x1),

x1 + x2 == 2 x, y1 + y2 == 2 y}, {x1, x2, y1, y2}] // Expand

发布者:Cara,转载请注明出处:http://www.makercollider.com/course/1783

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