MathDB
Trigonometric inequality

Source: Baltic Way 2005/2

November 7, 2005
inequalitiestrigonometryalgebra proposedalgebra

Problem Statement

Let α\alpha, β\beta and γ\gamma be three acute angles such that sinα+sinβ+sinγ=1\sin \alpha+\sin \beta+\sin \gamma = 1. Show that tan2α+tan2β+tan2γ38.\tan^{2}\alpha+\tan^{2}\beta+\tan^{2}\gamma \geq \frac{3}{8}.