An Overview of Eccentricity

A detailed tutorial on eccentricity. Step by step tutorial including sample problems and a visual representation of eccentricity for reference.

Eccentricity is a parameter associated with every conic section. Another way to think of it is as a measure of how much the conic section deviates from being circular. Each shape has a different eccentricity. The eccentricity of a circle is zero – because it does not deviate at all from being circular. The eccentricity of an ellipse that is not a circle is less than one but greater than zero, because it is almost a circle. The eccentricity of a parabola is one, and the eccentricity of a hyperbola is greater than one. Eccentricity plays an important part in calculations because two conic sections are only similar if they have the same eccentricity.