1971 AHSME Problems/Problem 19
If the line intersects the ellipse exactly once, then the value of is
Plug in into the ellipse's equation to find the intersection points: After simplifying, we have a quadratic in :
Because there is only one intersection point, then the quadratic has only one solution. This can only happen when the discriminant is 0.
Solving, we find The answer is
-edited by coolmath34