Incorrect. The domain must exclude any values for a that make the denominator have a value of 0. What values for a will make $\displaystyle{{a}}^{{3}}={0}\usepackage{cmbright}\Huge\$ ? Remember that $\displaystyle\frac{{{a}}^{{2}}}{{{a}}^{{3}}}={{a}}^{{{2}-{3}}}={{a}}^{{-{1}}}=\frac{{1}}{{a}}\usepackage{cmbright}\Huge\$ .