= Einstein-de Sitter density-growth modes
{c}
{title2=$\delta=C_+t^{2/3}+C_-t^{-1}$}
For pressureless <linear cosmological density perturbations> in an <Einstein-de Sitter universe>, $H=2/(3t)$ and $4\pi G\bar\rho_m=2/(3t^2)$. The growth equation is an <Euler differential equation> whose indicial equation is $(p-2/3)(p+1)=0$. Hence the independent modes are $\delta_+\propto t^{2/3}\propto a$ and $\delta_-\propto t^{-1}\propto a^{-3/2}$. The first is the growing <linear growth factor>, while the second is a decaying transient.
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