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PRELIMINARY CONSTRUCTIONS |
| Section: Geometry | |
| 1. THE MIDPOINT OF A SEGMENT | |
| In the following window M is the midpoint of the segment PQ. | |
| 1.-
Check that point M moves whenever points P or Q move so that it is
always equidistant between the two.
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| 2. THE PERPENDICULAR | ||
| In the following window there is a line drawn which is perpendicular to line PQ , which also passes through the midpoint M. | ||
| 1.-
You will notice that lots of straight
lines are produced quickly by moving point P.
2.- Drag point P or Q and look carefully at the trace produced by the straight lines. We will be using this trace to draw conic sections, so it is important that we understand how it is produced.
3.-
Now move point P by using
the arrows in the lower part of the window. Although we could
move point P by dragging it with the mouse, we get a
much smoother trace if we use the arrows as the lines are drawn at
uniform speed. |
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| Agustín Muñoz Núñez | ||
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| Spanish Ministry of Education. Year 2001 | ||
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