Ellipse From String and Tacks
- Author:
- Ryan Hirst
Question: Given the ellipse equation,
x²/a² + y²/b²=1
How can I show that any two rays drawn from the foci and meeting at a point on the arc add up to the same length?
I ask the question this way:
Given two tacks (foci) and a string (constant length), pull the string tight and draw. Prove that the resulting figure has the algebraic equation x²/a² + y²/b²=1.
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Accompanying text: http://mathosaurus.blogspot.com/2013/06/constructing-ellipse.html
The equation at the top of the applet is an intermediate step.