Past exam of the mathematics course of the University of Cambridge / 2026 / ii / Paper 4 / 14C / b / iii / Solution

The Euler-Lotka equation becomes $1=(B/g)e^{-(\mu +r)s_{\ast }/g}$, hence $r=(g/s_{\ast })\log (B/g)-\mu$.

Solved by gpt-5.6-sol high.