1. The problem statement, all variables and given/known data Normalise Ψ(x,0) (use the fact that both ψ1 and ψ2 are stationary states). Will this wave function be normalised at any later time, t > 0? 2. Relevant equations A particle in an infinite square well of width a has as its initial wave function an even mixture of the first two stationary states, Ψ(x, 0) = A(ψ1(x) + ψ2(x)) . 3. The attempt at a solution I get the concept of normalisation I would integrate the square of A(ψ1(x) + ψ2(x)) between 0 and a and equate it to 1. I am confused how to integrate ψ1(x) or ψ2(x) i.e. is it as simple as (ψ1(x)*x)/2? Perhaps I can say ψ1(x) = the time-independent Schr ̈odinger equation for the infinite square well un=(2/L)^0.5sin(nx/L) Anyway any help would be deeply appreciated, thanks.