The amplitude of a standing wave function representing a moving particle can change from positive to negative values in the domain (0, a) over which the wave function is defined. It must therefore pass through zero at some value x₀, where 0 < x₀ < a. Therefore the probability of the particle being at x₀ is zero and the particle cannot get from a position x < x₀ to a position x > x₀. Is this reasoning correct?