y= căn3 Sinx+ Cosx trên đoạn [-pi/3; pi/6]
[tex]y=2cos\left ( x-\frac{\pi }{3} \right ),x\in \left [ \frac{-\pi }{3} ;\frac{\pi }{6}\right ]\Rightarrow cos\left ( x-\frac{\pi }{3} \right )\in \left [ \frac{-1}{2};\frac{\sqrt{3}}{2} \right ]\Leftrightarrow maxy=\sqrt{3}[/tex]