Past exam of the mathematics course of the University of Cambridge / 2021 / ii / Paper 4 / 14E / e / Solution

The speed is positive for $r<1/2$, zero at $1/2$, and negative for $r>1/2$. The state with the larger basin-weighted reaction potential invades the other; raising the Allee threshold favours extinction.

Solved by gpt-5.6-sol high.