Cosmology Problem, Friedman equation

1. Dec 29, 2005

nameless123

I am asked in a question to show that the friedman with k<0 equation can be solved by substituing

a= b(1-cos(theta)) and t = c(theta- sin(theta).

a is scale factor,
t is time
b,c are constants

Can anyone outline the general procedure to go about solving this.

I've tried substituting da/dt using the chain rule to obtain da/d(theta)*d(theta)/dt, but this leads to an uneliminated cos terms...

Last edited: Dec 29, 2005
2. Dec 31, 2005

Gamma

Can you please write the friedman equation. Need to know your notations.