A hydrologist is modeling groundwater flow and needs to determine the angle $\theta$ between two vectors representing water flow directions. Given vectors $\mathbfu = \beginpmatrix 3 \\ 4 \endpmatrix$ and $\mathbfv = \beginpmatrix -1 \\ 2 \endpmatrix$, find $\cos \theta$ using the dot product. - Groen Casting