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Compute the sum of the vectors $\begin{pmatrix} \cos 0 \\ \sin 0 \end{pmatrix} + \renewcommand{\arraystretch}{1.5} \begin{pmatrix} \cos \frac{2 \pi}{11} \\ \sin \frac{2 \pi}{11} \end{pmatrix} \renewcommand{\arraystretch}{1} + \renewcommand{\arraystretch}{1.5} \begin{pmatrix} \cos \frac{4 \pi}{11} \\ \sin \frac{4 \pi}{11} \end{pmatrix} \renewcommand{\arraystretch}{1} + \dots + \renewcommand{\arraystretch}{1.5} \begin{pmatrix} \cos \frac{20 \pi}{11} \\ \sin \frac{20 \pi}{11} \end{pmatrix} \renewcommand{\arraystretch}{1}.$