Mathematics - Application of Derivative Question with Solution | TestHub

: Since ${\mathrm{x}}^2+{\mathrm{y}}^2=25\Rightarrow \mathrm{x}=5\cos \theta$ and $\mathrm{y}=5\sin \theta$ So, therefore, ${\log }_5(3\mathrm{x}+4\mathrm{y})={\log }_5(15\cos \theta +20\sin \theta )$

$\Rightarrow {\left\{{\log }_5(3\mathrm{x}+4\mathrm{y})\right\}}_{\text{max }}=2$