The radial wave equation for hydrogen atom is $\Psi = \frac{1}{16\sqrt{4}} \left(\frac{1}{a_o}\right)^{3/2} [(x-1)(x^2 - 8x + 12)] e^{-x/2}$ where $x = \frac{2r}{a_o}$, $a_o$ = radius of first Bohr orbit. The minimum and maximum position of radial nodes from nucleus are: