Eccentricity: how much a conic section (a circle, ellipse, parabola or hyperbola)
varies from being circular.
A circle has an eccentricity of zero, so the eccentricity shows you how "un-circular" the curve is. Bigger eccentricities are less curved.
Different values of eccentricity make different curves:
- At eccentricity = 0 we get a circle
- for 0 < eccentricity < 1 we get an ellipse
- for eccentricity = 1 we get a parabola
- for eccentricity > 1 we get a hyperbola
- for infinite eccentricity we get a line
Eccentricity is often shown as the letter e (don't confuse this with Euler's number "e", they are totally different)
Try the slider to see what happens:
Calculating The Value
|For a circle, eccentricity is 0|
For an ellipse, eccentricity is:
|For a parabola, eccentricity is 1|
For a hyperbola, eccentricity is: