Past exam of the mathematics course of the University of Cambridge / 2026 / ib / Paper 1 / 16C / iv / Solution

At $x=1$, direct substitution gives a product of odd half-integers. Taking logarithms and applying the hinted lower Riemann-sum estimate yields $\log \Pi (1)>n\log (2/e)$, hence $\Pi (1)>(2/e{)}^n$.

Solved by gpt-5.6-sol high.