Question:
Show that the area of a parallelogram whose diagonals are represented by \(\vec{a}\) and \(\vec{b}\) is given by \(\frac{1}{2}|\vec{a}\times\vec{b}|.\) Also find the area of a parallelogram whose diagonals are \(2\hat{i}-\hat{j}+\hat{k}\) and \(\hat{i}+3\hat{j}-\hat{k}\).