Eccentricity of Ellipse in terms of Semi-Major and Semi-Minor Axes/Mistake

Source Work

2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.):

ellipse

Mistake

Alternatively [the eccentricity] is given by

$e^2 - 1 - \dfrac {b^2} {a^2}$

Correction

This should of course read:

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

This glitch does not appear in the second edition.

Sources

• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): ellipse