Foci of an ellipse

2 videos
4 skills
Learn about the foci of an ellipse, which are two points for which the sum of the distances from any point on the ellipse is constant.

Finding the foci of an ellipse using an interactive widget (example)

VIDEO 6:27 minutes
Sal is given an ellipse within a special interactive widget, that shows the sum of distances of each point on the ellipse from the potential foci. He uses this widget to find the exact location of the foci.

Find the foci of an ellipse from its graph

PRACTICE PROBLEMS
Given the graph of an ellipse, use our special widget in order to determine its foci.

Finding the foci of an ellipse from its equation

VIDEO 13:49 minutes
Sal explains how the radii and the foci of an ellipse relate to each other, and how we can use this relationship in order to find the foci from the equation of an ellipse.

Find the foci of an ellipse from its radii

PRACTICE PROBLEMS
Given the major and minor radii of an ellipse, find its foci.

Find the foci of an ellipse from its equation

PRACTICE PROBLEMS
Given the equation of an ellipse, find its foci.

Write the equation of an ellipse from its foci and other features

PRACTICE PROBLEMS
Given the foci of an ellipse (and some other feature), find its equation.