Changes

To construct an ellipse, place tacks at two points on a piece of paper with a string between them. Trace out the curve of the ellipse with a pencil which is always pushing against the string. The longer the string, the less eccentric the ellipse will be (and more circular).

To construct an ellipse, place tacks at two points on a piece of paper with a string between them. Trace out the curve of the ellipse with a pencil which is always pushing against the string. The longer the string, the less eccentric the ellipse will be (and more circular).

The general algebraic formula for an ellipse is given by:

The general [[algebra]]ic formula for an ellipse is given by:

:<math>ax^2 + bxy + cy^2 + dx + ey + f = 0</math>

:<math>ax^2 + bxy + cy^2 + dx + ey + f = 0</math>