Recent content by thecoop

Thank you very much clamtrox

i don't know with what command i can do this !

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...

Hi guys I have 5 term which each term includes three function of time (autonomous system ), i want to obtain time derivative of each term as other terms for example if i define each term as a dimensionless variable , e.g. x , y , z , v , w , i want to know dx/dt = as a combination of x , y ...

Hello guys , beside Einstein's General Theory of Relativity by hervik , is there any lecture or book about this case ? Thx

the eotvos experiment consists of two objects of different composition connected by a rod of length l and suspended horizontally by a fine wire . if the gravitational acceleration of the two masses is different then there will be a torque , I saw this equation in the most of texts without...

In f(R) gravity as http://en.wikipedia.org/wiki/F%28R%29_gravity , i have problem with the term [ g_ab □ - ∇_a ∇_b ] F(R) , well actually is [ ∇_b ∇_a - ∇_a ∇_b ] F(R) , but F is a function of Ricci Factor and Ricci Factor is expressed as a(t) ( scale factor ) . for the a = b = 0 i say this...

hi guys , i want to write a complicated differential equation as autonomous equations , is there any method ? i have no idea to overcome it ! thank you

i want to derive the autonomous equations for that but don't know how to do

hi guys , can someone help me with references about this case ? thx

hey guys , is there anybody here to give me a nice reference for f(R) gavity ? Regards thecoop