## This is an unpublished test document with $LaTeX - Code$ in it. For example, $$\sqrt{3x-1}+(1+x)^2$$ is an squareroot.

• $\left( \sum_{k=1}^n a_k b_k \right)^2 \leq \left( \sum_{k=1}^n a_k^2 \right) \left( \sum_{k=1}^n b_k^2 \right)$