@Preben Alsholm Thanks a lot. But I have some new problems, now. After, solving this equation we want to solve another equation (ODE), that with your new version of fsolve, maple does not solve it. The ODE is:

> l := dsolve({D(L)(z) = L(z)/(1+z)+(1+z)*h/Y(z),L(0)=0}, type=numeric, range=0..2,known=Y);

Also, my final goal to find Y for large values of z was to determne some integrals of Y(z), where I couldn't get their results as a number. This problem exists yet. For example:

> A1 := ((0.35/Y(0.35))*(int(1/Y(z), z = 0 .. 0.35))^2)^(1/3);              and:

> R := h*evalf(sqrt(m)*(int(1/Y(z), z = 0 .. 1091.3)));

For the first integral I could find result before, but with your new reply I can't. What's the problem?

Also, I have a question. Is the starting value in fsolve shows the value of H at z=0? If it is right I must set H=h, for my physical concept and then what does your last reply mean?

Thank you very much. 

Your suggestion works for my example Y(185), but how about Y(1000)?

Your suggestion works for my example Y(185), but how about Y(1000)?

Thank you very much. But my program is not as simple as your example. I solve:

ode2 := diff(phi(z), z)-sqrt(2*sqrt(Omega(z))/(3*n)+.27*(1+z)^4*(diff(exp(phi(z)), z))/(3*Omega(z)*H(z)^2))/((1+z).H(z)) = 0;

by:     a := solve(ode2, diff(phi(z), z));

and then I get 2 answers. I want to choose the first one to use in solving a system of equations. The method that you proposed don't show the result as a differential equation because it doesn't include  diff(phi(z), z) in the left hand side. What should I do? I can make a new ode and write  diff(phi(z), z) = a[1]; This works, but I'm not sure that a[1] is the same every time I run the program. 

Also, do you think the order of the results always is the same?

thanks a lot.

Thank you very much. But my program is not as simple as your example. I solve:

ode2 := diff(phi(z), z)-sqrt(2*sqrt(Omega(z))/(3*n)+.27*(1+z)^4*(diff(exp(phi(z)), z))/(3*Omega(z)*H(z)^2))/((1+z).H(z)) = 0;

by:     a := solve(ode2, diff(phi(z), z));

and then I get 2 answers. I want to choose the first one to use in solving a system of equations. The method that you proposed don't show the result as a differential equation because it doesn't include  diff(phi(z), z) in the left hand side. What should I do? I can make a new ode and write  diff(phi(z), z) = a[1]; This works, but I'm not sure that a[1] is the same every time I run the program. 

Also, do you think the order of the results always is the same?

thanks a lot.

O.K. In my program there is a set of equations where I want to solve it in the loop. T is an array that I define just before the loop. This array has 4 columns and I don't know how many rows there are. I interrupted the program myself, because I found that it takes very much time.  

Thanks a lot, but I solved system myself in a different way.

Thanks a lot, but I solved system myself in a different way.

@Dave L Dear Dave

My question is "how can I obtain the solution further right of ...?". Is there any way to obtain it or not? I'm sorry, but I really did not find out the previous explanations. That's enough if you just tell me "yes" or "no".

thanks a lot. 

@Dave L Dear Dave

My question is "how can I obtain the solution further right of ...?". Is there any way to obtain it or not? I'm sorry, but I really did not find out the previous explanations. That's enough if you just tell me "yes" or "no".

thanks a lot. 

Thanks for your reply. I don't understand what you mean. Can you explain more, please?

Thanks for your reply. I don't understand what you mean. Can you explain more, please?

Thanks a lot. I have a new question. If I run the program with what you said there is a warning:

"can not evaluate the solution further right of 061111973". If I need the solution further right of it what should I do? 

Thanks a lot. I have a new question. If I run the program with what you said there is a warning:

"can not evaluate the solution further right of 061111973". If I need the solution further right of it what should I do? 

Thank you but I really did it. I tried maxfun=500000 and also maxfun=1000000 and more, many times but the error does not solve.