2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/89058A nonperturbative procedure of solving the time-dependent Schrödinger equation, called the multi-projection approach or phase dynamics of quantum mechanics, is derived and illustrated. In addition to introducing a method with that time-dependent systems become solvable (under the assumption that corresponding time-independent systems are solvable), the new approach unveils several misconcepts related to the usual wavefunction expansion and the standard perturbation theory.15 pages, 2 figures, latex, Changed contentQuantum Physicstext