Past exam of the mathematics course of the University of Cambridge / 2026 / ib / Paper 1 / 13B / iv / Solution

Only odd stationary states contribute, and for $j=2n+1$ their squared coefficients are $128/[{\pi }^2(j^2-16{)}^2]$. Since $E_{av}/E_1=16$, substitution givesso $B=8$.

Solved by gpt-5.6-sol high.