rectangular coordinates and polar coordinates are related to each other by the following relation
[tex]\begin{cases}x=r\cos \theta \\ y=r\sin \theta\end{cases}[/tex]
On polar coordinates, the first coordinate is the radius and the second the angle. Using this information, we have
[tex](6,\frac{11\pi}{6})\rightarrow\begin{cases}x=6\cos \frac{11\pi}{6} \\ y=6\sin \frac{11\pi}{6}\end{cases}[/tex]
Solving thiose expressions, we have
[tex]\begin{cases}x=6\cos \frac{11\pi}{6}=6\cdot(\frac{\sqrt[]{3}}{2})=3\sqrt[]{3} \\ y=6\sin \frac{11\pi}{6}=6\cdot(-\frac{1}{2})=-3\end{cases}[/tex]
Then, the coordinates of the point Q are
[tex](3\sqrt[]{3},-3)[/tex]
