\[\begin{array}{l}
e)\,\,\,y = 4\sin x + 5\\
Vi\,\, - 1 \le \sin x \le 1\\
\Rightarrow - 4 \le 4\sin x \le 4\\
\Leftrightarrow 1 \le 4\sin x + 5 \le 9\\
\Rightarrow \left\{ \begin{array}{l}
Min\,\,y = 1\,\,\,khi\,\,\,\sin x = - 1\\
Maxy = 9\,\,\,khi\,\,\sin \,\,x = 1
\end{array} \right..\\
\Rightarrow G = \left[ {1;\,\,9} \right].\\
f)\,\,\,y = 4 - 3\cos 2x\\
Vi\,\,\, - 1 \le \cos 2x \le 1\\
\Rightarrow - 1 \le - \cos 2x \le 1\\
\Leftrightarrow - 3 \le - 3\cos 2x \le 3\\
\Leftrightarrow 1 \le 4 - 3\cos 2x \le 7\\
\Rightarrow \left\{ \begin{array}{l}
Min\,\,y = 1\,\,khi\,\,\,\cos 2x = 1\\
Max\,\,y = 7\,\,khi\,\,\,cos2x = - 1
\end{array} \right..\\
\Rightarrow G = \left[ {1;\,\,7} \right].\\
g)\,\,\,y = {\sin ^2}x + 3\\
Vi\,\,\,0 \le {\sin ^2}x \le 1\\
\Rightarrow 3 \le {\sin ^2}x + 3 \le 4\\
\Rightarrow \left\{ \begin{array}{l}
Min\,y = 3\,\,khi\,\,\,\sin x = 0\\
Maxy = 4\,\,\,khi\,\,\,\sin x = 1 \Leftrightarrow \cos x = 0
\end{array} \right..\\
\Rightarrow G = \left[ {3;\,\,4} \right].
\end{array}\]
Các câu khác em làm tương tự nhé!!!
