(iv)

Compute the cross product $\mathbf{a} \times \mathbf{b}$ and $\mathbf{b} \times \mathbf{a}$. Check your answer by showing that each $\mathbf{a}$ and $\mathbf{b}$ are perpendicular to $\mathbf{a} \times \mathbf{b}$ and $\mathbf{b} \times \mathbf{a}$.