N}}{{x}^{n}}\] or \[\frac{dy}{dx}={{a}^{1-n}}n{{x}^{n-1}}\] \[sub-normal=\LEFT| y\frac{dy}{dx} \right|=\left| y{{a}^{1-n}}n{{x}^{n-1}} \right|\] \[=\left| {{a}^{1-n}}{{x}^{n}}{{a}^{1-n}}n{{x}^{n-1}} \right|=\left| {{a}^{2-2n}}{{x}^{2n-1}} \right|\] which is CONSTANT if \[2n-1=0\] or \[n=1/2\].