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三角形的直線與穿過對角頂點和外心的另一條直線的交點

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三角形的直線與穿過對角頂點和外心的另一條直線的交點

我有以下程式碼：

      pair a; pair b; pair c;
      pickup pencircle scaled 0.2pt;
      a = (0, 4cm); b = (-2cm, 0); c = (1cm, 0);
      draw a -- b -- c -- cycle;
      pair p; pair q; pair r; pair d; pair m; pair n;
      p = whatever[b, c]; a - p = whatever * (b - c) rotated 90;
      q = whatever[c, a]; b - q = whatever * (c - a) rotated 90;
      r = whatever[a, b]; c - r = whatever * (a -b) rotated 90;
      d = whatever[a, p] = whatever[b, q]; % orthocenter
      n = 1/4(a + b + c + d); % remarkably...
      m = d rotatedabout(n, 180); % M is also the circumcentre
      path circumcircle;
      circumcircle = fullcircle scaled 2 abs(m - a) shifted m;
      draw circumcircle;
      pair l;
      pickup pencircle scaled 2pt;
      drawdot m;
      pickup pencircle scaled 0.2pt;
      %draw a -- ((a -- m) intersectionpoint (b -- c));

我可以計算外心並且它有效。但未註解的最後一行註解告訴我路徑不相交。難道是AM不擴展與BC進行交集計算的情況嗎？我認為我可以用shifted關鍵字來管理它，但不知道如何做。任何幫助都感激不盡。

答案1

我設法將最後一行更改為以下內容：

draw a -- (a -- (a - 100(a - m))) intersectionpoint (b -- c);

並獲取線路。看來這條線需要延長才能intersectionpoint運作。

答案2

如果您想遵循與之前的程式碼相同的風格，您也可以這樣做

pair q ; q = whatever[a,m] = whatever[b,c] ;
draw a -- q ;

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