1. The problem statement, all variables and given/known data I am struggling to understand all the steps in a derivation involving a normalisation of a particular wavefunction. I get most of the steps. I have attached the derivation and put a star next to the steps I don't fully understand. 2. Relevant equations Listed on attachment. 3. The attempt at a solution For the first step I have starred, I get that the integral from - to + infinity for an even function is twice the integral from 0 to infinity but how do you know that this is an even function in the example? For the next bit why does -2lambda appear on the denominator? I don't get what the derivation is getting at in the final step - how do they know that A is real? and why do they write A*A - is it because the absolute square of A is A multiplied by its complex conjugate which in this case is 1 (as it disappears in the 4th step) so therefore you know A is real? Thanks for any help offered!