Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2015-part-01 — 191 problems (EN–VI) Question 40

Math Olympiad Vault · MathNet 2015-part-01 — 191 problems (EN–VI)

Question 40

Let $a$, $b$, $c$ be the lengths of the sides of a given triangle and $m_a$, $m_b$, $m_c$ be the lengths of the corresponding medians. Prove that:
$$
m_a \left(\frac{b}{a} - 1\right) \left(\frac{c}{a} - 1\right) + m_b \left(\frac{a}{b} - 1\right) \left(\frac{c}{b} - 1\right) + m_c \left(\frac{a}{c} - 1\right) \left(\frac{b}{c} - 1\right) \geq 0.
$$