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1 files changed, 38 insertions, 0 deletions
diff --git a/info/drawing-with-metapost/src/tangents-point-to-circle.mp b/info/drawing-with-metapost/src/tangents-point-to-circle.mp
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+++ b/info/drawing-with-metapost/src/tangents-point-to-circle.mp
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+\documentclass{standalone}
+\usepackage{luamplib}
+\begin{document}
+\mplibtextextlabel{enable}
+\begin{mplibcode}
+beginfig(1);
+path C, C'; pair p, t, t';
+C = fullcircle scaled 100;
+p = 189 right rotated 30;
+
+C' = fullcircle zscaled p shifted 1/2 p;
+% t = C intersectionpoint C';
+% t' = reverse C intersectionpoint C';
+t = C intersectionpoint halfcircle zscaled p shifted 1/2 p;
+t' = C intersectionpoint halfcircle zscaled -p shifted 1/2 p;
+
+drawoptions(dashed withdots scaled 1/4 withcolor (.2, .2, .7));
+draw C'; draw t -- center C -- p;
+
+drawoptions(withcolor (.2, .2, .7));
+dotlabel.lrt("$m$", 1/2 p);
+dotlabel.llft("$o$", center C);
+
+drawoptions(dashed evenly);
+draw t -- p -- t';
+
+drawoptions();
+draw C;
+label.llft("$C$", point 5 of C);
+
+dotlabel.urt("$p$", p);
+dotlabel.ulft("$t$", t);
+dotlabel.bot("\strut $t'$", t');
+
+endfig;
+\end{mplibcode}
+\end{document}
+