Write Up #6
by Keith Leatham
10. Construct the locus of points equidistant
from a fixed point F and a circle. In other words,
repeat the parabola construction but use a circle as the "directrix."
Let F be any point in the plane
other than the center of the circle. Assume F is not on the circle;
it can be either inside or outside.
a. Use an Action Button to generate the parabola from an animation
and trace of a
constructed point.
b. Repeat 10a with a trace of the tangent line at the constructed
point.
c. Use the locus command to generated the parabola from a constructed
point or the
tangent line at that point.
a. Point Generation of Locus--In
this GSP document, moving point B will change the size of circle
A, F is any point in the plane other than the center of the circle,
and the point H constructs the locus we are looking for.
b. Tangent Line Generation
of Locus--In this GSP document, line k outlines the locus.
c. Locus Command Generation
of Locus--In the GSP document, the locus of points is automatically
generated by the Locus command. Many different configurations
can be seen by moving point F.
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