Definition:Eccentric Angle/Ellipse
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Definition
Let $\KK$ be an ellipse with foci at $F_1$ and $F_2$.
Let $P$ be a point on $\KK$.
Let $\CC$ be the auxiliary circle of $\KK$ with center $O$.
Let $PQ$ be dropped perpendicular to the major axis $F_1 F_2$ of $\KK$ such that $Q$ lies on $F_1 F_2$.
Let $QP$ be produced so as to meet $\CC$ at $P'$.
The angle $QOP'$ is the eccentric angle of $P$ with respect to $\KK$.
In the above diagram, $\alpha$ is the eccentric angle of $P$ with respect to $\KK$.
Also see
- Results about eccentric angles can be found here.
Sources
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): ellipse
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): ellipse