Olympiad Maths Prep

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Problem 535

AMC 12 late, AIME early
Algebra Difficulty 4.9 Prove it

2. Prove for real numbers a0,ba \neq 0, b the inequality

a2+b2+2a2+2ba2 a^{2}+b^{2}+\frac{2}{a^{2}}+\frac{2 b}{a} \geqslant 2

This one wants a proof. Work it on paper, read the official solution, then mark yourself honestly — the ladder only means something if the record is true.

Official solution

2. The solution follows from the following inequality:

(a1a)2+(b+1a)20 \left(a-\frac{1}{a}\right)^{2}+\left(b+\frac{1}{a}\right)^{2} \geqslant 0

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.