Question

What is the eccentricity of an ellipse?

Answer 1

Eccentricity of an ellipse

The eccentricity of an ellipse is the ratio of the distance between the center of the ellipse and each focus to the length of the semimajor axis.

The eccentricity of an ellipse is always less than $1$

The eccentricity of an ellipse $\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$ is,

$e=\sqrt{1-\frac{b^2}{a^2}}$

Where, $a=$ the length of the semi-major axis

$b=$ the length of semi-minor axis