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Foci of an ellipse
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.
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.
Given the graph of an ellipse, use our special widget in order to determine its foci.
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.
Given the major and minor radii of an ellipse, find its foci.
Given the equation of an ellipse, find its foci.
Given the foci of an ellipse (and some other feature), find its equation.