if it found itself confined to the interior of a box, or attached to the end of a spring, or circling around a proton - we have to put in the Equation how \(V\) depends on the coordinates. If you put ...if it found itself confined to the interior of a box, or attached to the end of a spring, or circling around a proton - we have to put in the Equation how \(V\) depends on the coordinates. If you put this into Equation \(\ref{7.8.3}\) (all you have to do is to note that \(\nabla^2 \Psi = \chi \nabla^2 \psi\) and that \(\Psi = \psi \chi\)), you find that the time-independent part of Schrödinger's Equation satisfies