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MathNet 2015-part-07 — 185 problems (EN–VI) Question 50

Math Olympiad Vault · MathNet 2015-part-07 — 185 problems (EN–VI)

Question 50

Let $I$ be the set of points $(x, y)$ in the Cartesian plane such that

$$
x \gt \left( \frac{y^{4}}{9} + 2015 \right)^{1/4}
$$

Let $f(r)$ denote the area of the intersection of $I$ and the disk $x^{2} + y^{2} \leq r^{2}$ of radius $r \gt 0$ centered at the origin $(0,0)$. Determine the minimum possible real number $L$ such that $f(r) \lt L r^{2}$ for all $r \gt 0$.