Question Number 188128 by Rupesh123 last updated on 26/Feb/23
Answered by mr W last updated on 26/Feb/23
$${WLG},\:{assume}\:{a}\leqslant{b}\leqslant{c}. \\ $$$$\mathrm{cos}\:{C}=\frac{{a}^{\mathrm{2}} +{b}^{\mathrm{2}} −{c}^{\mathrm{2}} }{\mathrm{2}{ab}} \\ $$$$\mathrm{2}{b}×\mathrm{cos}\:{C}=\frac{{a}^{\mathrm{2}} +{b}^{\mathrm{2}} −{c}^{\mathrm{2}} }{{a}}={a}+\frac{{b}^{\mathrm{2}} −{c}^{\mathrm{2}} }{{a}}\leqslant{a} \\ $$
Commented by Rupesh123 last updated on 26/Feb/23
Nice!