Apoapsis
The greatest radial distance of an Ellipse as measured from a Focus. Taking 
in the equation of anEllipse
gives the apoapsis distance
Apoapsis for an orbit
around the Earth 
is called apogee, and apoapsis for anorbit around the Sun is called aphelion. See also Eccentricity, Ellipse, Focus, Periapsis- Euler Characteristic
- Euler Constant
- Euler Curvature Formula
- Euler Differential Equation
- Euler Equation
- Euler Formula
- Euler Four-Square Identity
- Euler Graph
- Eulerian Circuit
- Eulerian Cycle
- Eulerian Integral of the First Kind
- Eulerian Integral of the Second Kind
- Eulerian Number
- Eulerian Trail
- Euler Identity
- Euler Integral
- Euler-Jacobi Pseudoprime
- Euler-Lagrange Derivative
- Euler-Lagrange Differential Equation
- Euler L-Function
- Euler Line
- Euler-Lucas Pseudoprime
- Euler-Maclaurin Integration Formulas
- Euler-Mascheroni Constant
- Euler-Mascheroni Integrals