Vector Algebra

$\left(\frac{a-b}{a^2 b^2}\right)^2$

$\left(\frac{\mathbf{a}-\mathbf{b}}{\mathbf{a b}}\right)^{\mathbf{2}}$

$\left(\frac{b \mathbf{a}-a \mathbf{b}}{a b}\right)^2$

$\left(\frac{a \mathbf{a}-b \mathbf{b}}{a^2 b^2}\right)^2$