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  How to find solution of Friedman equation numerically ?

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 I am trying to solve friedman acceleration equation and continuity equation numerically using Runge Kutta Dormand Prince Method . My code was doing excellent for solving coupled differential equations. But, when I am trying to solve this equation , I am getting wrong results , I am getting same variation of scale factor for both matter dominated and radiation dominated case while one should vary as a2/3 and other should vary as a1/2. Can someone please tell me the possible reasons why this is happen ?

                          \[\Ddota= -1/6(\rho + 3p)\]

Closed by author request
asked Aug 6, 2021 in Closed Questions by Doribez (5 points) [ no revision ]
recategorized Aug 16, 2021 by Dilaton

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