Thursday, July 13, 1995
We began the morning with an investigation of features of the version 3.0 of the Geometer's Sketchpad.
1. Annie gave us the following exercise:
- Open a new Sketchpad window and create x and y axes.
- Create three points, A, B, and X on the x axis, and
find their coordinates.
- Using the calculator, calculate the x coordinate of each
(hereafter these coordinates will be called simply
X, A, and B).
- The equation to plot is F(X) = AX + B
- Using the calculator, calculate AX + B
- Select X and this equation and, using the calculator,
plot x,y (graph menu).
- Move X along the x axis until the point x,y appears
on the screen.
- Find the locus of x,y as X moves along the x axis:
- Select X, the x axis, and x,y and construct
the locus (Construct menu).
- Move A and B and describe the results.
2. Next we looked at a geometric representation:
- draw line segment AB
- put a point C somewhere not on it (slightly above)
- construct a point X on the line and connect C and X
- select line CX and construct its perpendicular bisector
- select line CX and trace locus
- make an Animate button
- Question: How do you find the point on the perpendicular
bisector of CX that is on the parabola?