tìm min max y=5-2sinx

\[\begin{array}{l}
y = 5 – 2\sin x\\
Ta\,\,co:\,\, – 1 \le \sin x \le 1\\
\Rightarrow – 2 \le – 2\sin x \le 2\\
\Leftrightarrow 3 \le 5 – 2\sin x \le 7\\
\Rightarrow \left\{ \begin{array}{l}
Min\,y = 3\,\,\,khi\,\,\,\sin x = 1\\
Max\,\,y = 7\,\,khi\,\,\,\sin x = – 1
\end{array} \right..
\end{array}\]