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Ellipse Construction

By: a guest on May 27th, 2011  |  syntax: None  |  size: 0.66 KB  |  hits: 284  |  expires: Never
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  1. Manipulate[
  2.  u1 = {3 Sin[t], 2 Cos[t]} - {Sqrt[5], 0};
  3.  u2 = {3 Sin[t], 2 Cos[t]} + {Sqrt[5], 0};
  4.  n1 = u1/Norm[u1];
  5.  n2 = u2/Norm[u2];
  6.  Show[ParametricPlot[{3 Sin[x], 2 Cos[x]}, {x, 0, t}, Axes -> None,
  7.    PlotRange -> {{-3.1, 3.1}, {-2.1, 2.1}}],
  8.   Graphics[Join[
  9.     {PointSize[Large], Red, Point[{{Sqrt[5], 0}, {-Sqrt[5], 0}}],
  10.      Line[{{-Sqrt[5], 0}, {3 Sin[t], 2 Cos[t]}}],
  11.      Line[{{Sqrt[5], 0}, {3 Sin[t], 2 Cos[t]}}],
  12.      Blue, Point[{3 Sin[t], 2 Cos[t]}], Red, PointSize[Medium]},
  13.     {Point[Table[{Sqrt[5], 0} + n1  i, {i, 0, Norm[u1], 0.4}]]},
  14.     {Point[Table[{-Sqrt[5], 0} + n2  i, {i, 0, Norm[u2], 0.4}]]}
  15.     ]]
  16.   ], {t, 10^-4, 2 Pi}]