This applet shows a double slider construction of the ellipse. We imagine a metal bar connecting the red and white dots, and a metal bar connecting the white and orange dots. The distance between the red and white dots, and between the white and orange dots is constant. The red dot is free to move along the x-axis, and the white dot is free to move along the y-axis.
The result is that the orange dots will trace out an ellipse, the blue curve.
Use your mouse to grab the red dot in the center of the image and move it around to see what happens. In the upper left are two sliders that control the lengths of the parts of the metal bars connecting the red and white dots, and the white and orange dots.
| Made with JavaSketchpad |
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