Question 11
For any two positive real numbers $x$ and $y$ prove
$$
\log^2(xy) \ge \log(x^2)\log(y^2).
$$
$$
\log^2(xy) \ge \log(x^2)\log(y^2).
$$
MathNet 2015-part-02 — 191 problems (EN–VI) Question 11
Math Olympiad Vault · MathNet 2015-part-02 — 191 problems (EN–VI)