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[几何] 如何算出 E、F 点的复数坐标?条件见图。

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TSC999 posted 2022-2-3 22:38 |Read mode
一个证明题.png

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original poster TSC999 posted 2022-2-3 22:44
问题来源见下图。此图为史勇先生所创。据说他是按 “复对合” 理论算出的 E、F 点的复坐标。

史勇原图.jpg

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original poster TSC999 posted 2022-2-6 18:30
如何求 E 点坐标.png

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original poster TSC999 posted 2022-2-6 18:37
Last edited by TSC999 2022-2-6 20:51求 E 点坐标的程序代码:
  1. Clear["Global`*"];
  2. h = a^2 + b^2 + c^2;  
  3. \!\(\*OverscriptBox[\(h\), \(_\)]\) = 1/a^2 + 1/b^2 + 1/c^2;
  4. Timing[Simplify[
  5.   Solve[{Sqrt[(a^2 - b^2) (1/a^2 - 1/b^2)] Sqrt[(b^2 - e) (1/b^2 -
  6. \!\(\*OverscriptBox[\(e\), \(_\)]\))] == (a^2 - c^2) (1/a^2 -
  7.          1/c^2) - (b^2 - c^2) (1/b^2 - 1/c^2), (h - b^2)/(
  8. \!\(\*OverscriptBox[\(h\), \(_\)]\) - 1/b^2) == (e - b^2)/(
  9. \!\(\*OverscriptBox[\(e\), \(_\)]\) - 1/b^2)}, {e}, {
  10. \!\(\*OverscriptBox[\(e\), \(_\)]\)}]]]
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求 F 点坐标的程序代码:
  1. Clear["Global`*"];
  2. h = a^2 + b^2 + c^2;  
  3. \!\(\*OverscriptBox[\(h\), \(_\)]\) = 1/a^2 + 1/b^2 + 1/c^2;
  4. Timing[Simplify[
  5.   Solve[{Sqrt[(a^2 - c^2) (1/a^2 - 1/c^2)] Sqrt[(c^2 - f) (1/c^2 -
  6. \!\(\*OverscriptBox[\(f\), \(_\)]\))] == (a^2 - b^2) (1/a^2 -
  7.          1/b^2) - (b^2 - c^2) (1/b^2 - 1/c^2), (h - c^2)/(
  8. \!\(\*OverscriptBox[\(h\), \(_\)]\) - 1/c^2) == (f - c^2)/(
  9. \!\(\*OverscriptBox[\(f\), \(_\)]\) - 1/c^2)}, {f}, {
  10. \!\(\*OverscriptBox[\(f\), \(_\)]\)}]]]
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上面程序解出的 E、F 是未化简坐标,消除根式后正负号如何取? 可通过数字验证来判断。根式消除后,下一步可用软件来证明主帖中的史勇公式:

程序解出的 E、F 未化简坐标及化简结果.png

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