📘 algebra, vectors, matrices, arithmetic progression, compound interest

1. **Vector Magnitude Problem:** Given vectors \(\vec{OP} = 5\mathbf{i} - 3\mathbf{j}\) and \(\vec{OQ} = 3\mathbf{i} + 5\mathbf{j}\), find the magnitude of \(\vec{PQ}\). - \(\vec{P