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MathNet 2008-part-04 — 165 problems (EN–VI) Question 96

Math Olympiad Vault · MathNet 2008-part-04 — 165 problems (EN–VI)

Question 96

Find all pairs $(\alpha, \beta)$ of positive real numbers with the following properties:

a. For all positive real numbers $x, y, z, w$,
$$
x + y^{2} + z^{3} + w^{6} \geq \alpha (x y z w)^{\beta}
$$

b. There exists a quadruple $(x, y, z, w)$ of positive real numbers such that equality holds in (a).