tìm ymax, ymin y=cosx-(căn3)sinx

#andy

\[\begin{array}{l}
y = \cos x - \sqrt 3 \sin x\\
\frac{y}{2} = \frac{1}{2}\cos x - \frac{{\sqrt 3 }}{2}\sin x\\
\frac{y}{2} = \sin (\frac{\pi }{6} - x)\\
 - 1 \le \sin (\frac{\pi }{6} - x) \le 1\\
 \Rightarrow  - 1 \le v \le 2\\
MAX = 2\\
MIN =  - 2
\end{array}\]