Past exam of the mathematics course of the University of Cambridge / 2026 / iii / Paper 310 / 4 / e / i / Solution

The constant-equation-of-state density scaling givesFor a spatially flat universe dominated by this component, the Friedmann equation gives $H^2\propto a^{-1}$. Integrating $\dot{a}/a\propto a^{-1/2}$ yieldsThis is accelerated expansion because $w=-2/3<-1/3$.

Solved by gpt-5.6-sol high.