Question 85
Prove that
$$
|(a-b)(b-c)(c-d)(d-a)| \le \frac{abcd}{4},
$$
if real numbers $a, b, c, d$ belong to the segment $[1; 2]$.
$$
|(a-b)(b-c)(c-d)(d-a)| \le \frac{abcd}{4},
$$
if real numbers $a, b, c, d$ belong to the segment $[1; 2]$.
MathNet 2015-part-01 — 191 problems (EN–VI) Question 85
Math Olympiad Vault · MathNet 2015-part-01 — 191 problems (EN–VI)