1=ρ/3 H^2+x1+x2+x3+x4+x5
x1=ρ λ f/6 H^2
x2=-ρ λ f' R/6 H^2
x3=λ f" ρ R`/H
x4=3 λ f' ρ
x5=ρ^2 λ f' / 3 H^2
where H=a`(t) /a(t)
R=6(2H^2+H`)
f(R)
ρ(t)
λ Constant
f' = the first derivative wrt R
f"= the second derivative wrt R
R`=the first derivative wrt t
a`=the first...
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