1. The problem statement, all variables and given/known data Compute the horizon of the universe as a function of [tex]\Omega[/tex]m in a flat universe with both matter and a cosmological constant but no radiation. 2. Relevant equations Event horizon distance r = a(t)c [tex]\int_0^tcdt'/a(t')[/tex] 3. The attempt at a solution No idea how i'm going to be able to transform that integral into something I can do, Using the FRW equation you can get H2 = [tex]\Lambda/ 3([/tex][tex]\Omega[/tex]m -1) possibly using H = (da/dt)/a thus dt = da/aH ? and then if you do substitute for an integral in a would the limits be 0 to 1 as we set a = 1 at present or 0 to a?