Monday, 4 January 2016

Equation for ellipse with vertical Major Axis



The equation of an ellipse that has its major axis oriented vertically differs slightly from the standard form in that the terms a and b, which represent the lengths of the semi-major and semi-minor axes respectively, is swapped around.

It is given by...
\frac{x^2}{b^2} + \frac{y^2}{a^2} = 1
Notice that the semi-major axis a, now sits under y, the vertical coordinate.

Similarly, the coordinates and relationships for the features of the ellipse are also switched around:

The x-intercepts are given by: (±b, 0)
The y-intercepts are given by: (0, ±a)
The foci are given by: (0, ±ae)
The directrices are given by: (0, ±a/e)

In this video, we go through the following examples:

  1. Sketching the ellipse x2/49 + y2/64 = 1 and defining all features
  2. Sketching the ellipse (x-1)2/4 + (y+2)2/16 = 1 and defining all features

No comments:

Post a Comment