Past exam of the mathematics course of the University of Cambridge / 2026 / ii / Paper 2 / 10E / b / v / Solution

After $r$ iterations the marked amplitude is $\sin ((2r+1)\alpha )$. Choose $r$ nearest to $\pi /(4\alpha )-1/2$; for $M\ll N$, this is about $(\pi /4)\sqrt{N/M}$ oracle iterations.

Solved by gpt-5.6-sol high.