A parabola is drawn. An ellipse is drawn with one focus at the focus of the parabola and another focus on the line . Given that the ellipse is tangent to the parabola at coordinate , then find the maximum possible integer value of .
Details and Assumptions
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Suppose we start at the focus common to both the ellipse and the parabola, and shoot a point-like ball at the tangent point ( a , a 2 ) . Because the point bounces off the parabola, it will travel vertically after reflection. However, since it also bounces off the ellipse, it will travel to the ellipse's second focus. Thus, we know that the ellipse's second focus's x-coordinate is equal to a . Thus, a 2 ≤ 2 0 1 4 ⟹ a ≤ 2 0 1 4 ≈ 4 4 and we are done.