Browse · MATH
Printjmc
algebra senior
Problem
An ellipse has foci at and . It has two -intercepts, one of which is the origin. What is the other one? Enter your answer as an ordered pair.
Solution
The sum of the distances from to the two foci is By the definition of an ellipse, the sum of the distances from any point on the ellipse to the two foci must also be So, in particular, if is the other -intercept, the distance formula gives Drawing out the ellipse, we see that so we can drop the absolute values around Then, solving for , we have so Thus the answer is
Final answer
\left(\tfrac{15}{4},0\right)