## 175 Reputation

15 years, 64 days

## fsolve float issue...

Maple

Dear guys, Can anyone tell me why my program does not work for some initial values? All my equations are:

> alpha := (6*h^2)^(1-n)*(1-k)^(1-n)*((1-m+k)/(2*n-1-k));

> eq := z-> 1=(m*(1+z)^3-k*(1+z)^2)*h^2/(H^2)+(((2*n-1)-(k*(1+z)^2*h^2/H^2))*((1-m+k)/(2*n-1+k))*((((H^2/h^2)-k*(1+z)^2)/(1-k))^(n-1)));

> Y := z->if not type(z,numeric) then 'procname(z)' else (fsolve(eq(z), H=h)) end if;

> l := dsolve({D(L)(z) = L(z)/(1+z)+(1+z...

Maple

Dear guys

I have an expression and I solve it by "solve". It has two results and I want to choose first of them. How can I choose for example the first result? Is the order of results the same if I run the program many times?

## writting data float...

Dear guys

In my program I have a loop and after some calculation I want to write the results. I use:

" writedata("D:\\arvin\\bao-cmb-h.txt", convert(T, array), float);"

but maple give me an error:

" Error, (in convert/list) object too large "

how can I write my data?

Thanks.

## set-of-ODEs-stiff...

Maple

Dear guys

I have a set of ODEs but when I solve it maple shows this massage:

"Error, (in dsolve/numeric/SC/firststep) unable to evaluate the partial derivatives of f(x,y) for stiff solution"

If I neglect the option "stiff=true", it works but then when I want to plot something maple says:

"Warning, cannot evaluate the solution past the initial point, problem may be complex, initially singular or improperly set up"

and only shows a coordinate...

## evaluation a number...

Maple

Dear guys! My question is: "how can I evaluate x when I fix y for an example equation y:=x+x^2". for each value of x we have a value for y. we can obtain it for example with "eval". but how about in this case?

Thanks

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