## 175 Reputation

15 years, 64 days

## fsolve with unknown initial condition...

Maple

Daer all! I want to solve the following equation

> H(z)*(1-m*H(0)^2*(1+z)^3/H(z)^2)-2*e*sqrt(1-c^2)*sqrt(r)*H(0) = 0;

where H(0) denotes the value of H(z) at z=0 and other constants are

> m := 0.211: c := 0.80: r := 0.338: e := 1:

If I want to use the fsolve command as

> eq := z->H*(1-m*H(0)^2*(1+z)^3/H^2)-2*e*sqrt(1-c^2)*sqrt(r)*H(0) = 0;

> Y := z-> fsolve(eq(z), H=1):

what should I imply instead of H(0)?

## what does fsolve command do exactly?...

Maple

Dear guys! I have an equation as

> eq := z-> H*(1-m*h^2*H^(-2)*(1+z)^(3))-2*e*sqrt(1-c^2)*sqrt(r)*h=0:

where

> m := 0.211: h := 0.741: c := 0.80: r := 0.338: e := 1:

At this equation H is an unknown function of z, h is the value of H at z=0 and I want to obtain H(z) actually(for example the graph of H(z) for z=-1..5). So I did as following

> Y := z-> fsolve(eq(z), H=h):    **

plot(eval(H, H='Y(z)'), z=-1 .. 5);

## system of ODEs HDEDGP...

Maple

Dear guys!

I want to solve this system:

> c := 1: RC := 0.03: h := 1: m := 0.3:

> a := H(z)^2/(1+z)-h^2*(m*(1+z)^2+2*RC/(1+z));

> ode1 := diff(H(z),z) = (H(z)^4/((1+z)^2)+m*(1+z)*h^2*H(z)^2-2*m^2*h^4*(1+z)^4)/(2*H(z)*a) - (2*H(z)*h^2*RC)/(a*(1+z)^2) + (2*RC*h^2*(1+z)/(c*H(z)^2*a))*(H(z)^2/(1+z)^2-(H(z)^2/(1+z)-m*h^2*(1+z)^2)^2/(4*RC*h^2))^(3/2):

> ode2 := diff(M(z),z)=3*M(z)/(1+z)-2*M(z)*diff(H(z),z)/H(z):

> sys := {ode1, ode2}:

## seperating convexhull...

Maple

Dear all! I have 2 different lists:

ch1 := [[0.1e-1, -.56], [0.25e-1, -.57], [0.35e-1, -.555], [.115, -.43], [.16, -.3], [.195, -.24], [.28, -.155], [.315, -0.25e-1], [.32, -0.85e-1], [.41, .19], [.425, .11], [.425, .425], [.425, .43], [.425, .44], [.43, .12], [.43, .265], [.43, .405], [.43, .445], [.435, .295], [.435, .38], [.465, .44], [.5, .29], [.505, .31], [.505, .395], [.51, .37]];

ch2 := [[0.3e-1, -.5], [0.5e-1, .575], [.11, .495], [.15, -.295], [.19, -.33...

## problem in for loop...

Maple

nonflat1-bestfit-H0-.mw  sn_union2.txt  Hi all! Can anyone tell me what the problem is in my worksheet? It works for first two initial conditions but then it does not work. The data file that is needed to run the program has attached, too. Thanks.

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