Đáp án:
Giải thích các bước giải:
\(\begin{array}{l}
C1:\\
a.\left[ \begin{array}{l}
\sin x = \frac{5}{2}\left( l \right)\\
\sin x = - 1
\end{array} \right. \to \left[ \begin{array}{l}
x = - \frac{\pi }{2} + k2\pi \\
x = \frac{{3\pi }}{2} + k2\pi
\end{array} \right.\left( {k \in Z} \right)\\
b.\frac{1}{2}\sin x - \frac{{\sqrt 3 }}{2}\cos x = \frac{1}{2}\\
\to \cos \frac{\pi }{3}.\sin x - \sin \frac{\pi }{3}.\cos x = \frac{1}{2}\\
\to \sin \left( {x - \frac{\pi }{3}} \right) = \frac{1}{2}\\
\to \left[ \begin{array}{l}
x - \frac{\pi }{3} = \frac{\pi }{6} + k2\pi \\
x - \frac{\pi }{3} = \frac{{5\pi }}{6} + k2\pi
\end{array} \right. \to \left[ \begin{array}{l}
x = \frac{\pi }{2} + k2\pi \\
x = \frac{{7\pi }}{6} + k2\pi
\end{array} \right.\left( {k \in Z} \right)
\end{array}\)
