Question Number 128388 by enter last updated on 06/Jan/21
$${y}=−{sin}\left(\frac{\Pi}{\mathrm{2}}+\mathrm{2}{x}\right)+\mathrm{2}{cos}\left(\mathrm{5}{x}+\Pi\right) \\ $$$${y}_{{min}} =\:?? \\ $$
Commented by TheSupreme last updated on 07/Jan/21
$${y}=−{cos}\left(\mathrm{2}{x}\right)−\mathrm{2}{cos}\left(\mathrm{5}{x}\right)\geqslant−\mathrm{3} \\ $$$${y}=−\mathrm{3}\:{x}=\mathrm{10}{k}\pi \\ $$$$ \\ $$$$ \\ $$