Giải trắc nghiệm:

Câu 1:C
Câu 2: 
$\displaystyle  \begin{array}{{>{\displaystyle}l}}
-1\leqslant \sin 2x\leqslant 1\\
\Rightarrow -1\leqslant m+1\leqslant 1\\
\Rightarrow -2\leqslant m\leqslant 0
\end{array}$
B
Câu 3:
$\displaystyle  \begin{array}{{>{\displaystyle}l}}
\cos 2x=-1\\
\Rightarrow 2x=\pi +k2\pi \\
\Rightarrow x=\frac{\pi }{2} +k\pi \\
D
\end{array}$
Câu 4:
$\displaystyle  \begin{array}{{>{\displaystyle}l}}
\sin 2x=\frac{\sqrt{3}}{2}\\
\Rightarrow \left[ \begin{array}{l l}
2x=\frac{\pi }{3} +k2\pi  & \\
2x=\frac{2\pi }{3} +k2\pi  & 
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l l}
x=\frac{\pi }{6} +k\pi  & \\
x=\frac{\pi }{3} +k\pi  & 
\end{array} \right.
\end{array}$
B
Câu 5:
$\displaystyle  \begin{array}{{>{\displaystyle}l}}
-1\leqslant \sin 2x\leqslant 1\\
\Rightarrow -\sqrt{3} +1\leqslant y\leqslant \sqrt{3} +1
\end{array}$
A