Based on coherent states of the reversed harmonic oscillator, a wave function is proposed with the following three properties: (1) The mean values of position, r 0 , and velocity, v 0 , are parallel to the x axis; (2) The wave function is extended by a curve parameter w ≥ 0 such that, as a function of w, the mean values r w and v w describe a rectilinear orbit along the x axis with the mean initial values r 0 and v 0 ; (3) The mean energy is constant with respect to w by the leading order of the perturbation parameter . For comparison, the classical one-dimensional equation of motion is integrated. Exact analytical equivalence between classical and the = 0 quantum limit is found, both for positive and negative mean energy. The curve parameter w is in 1-1 correspondence with time t ≥ 0.