Eccentricity
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)
Animation
Try the slider to see what happens:
images/eccentricity-graph.js
Calculating The Value
For a circle, eccentricity is 0 | |
For an ellipse, eccentricity is: √a2 − b2a
| |
For a parabola, eccentricity is 1 | |
For a hyperbola, eccentricity is: √a2 + b2a
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