okay i got it. I made the mistake to assign digits than Digits. All works now.

I'm sorry, a typo

f:=1+x^2+1/100*ln(abs(3-4*x))=0;

That's what i mean.

okay, i see that these two ways of generating  index variables  have differences in the underlying data structure. I just thought there's a more fundamental reason to use one or the other. Thanks for pointing out the differences, Doug and Acer.

Thomas

okay, a time test also showed that Joe's method works much faster than mine. Building up a set with union takes its time.

Thomas

a set eliminates double elements by itself.

S:={}:while nops(S)<10 do S:=S union {rand(1..100)()};  end do:

S;

{3, 12, 19, 40, 49, 51, 53, 63, 67, 90}

To avoid repeated elements, one could use the member command to check if the element is already in your list/set.

Thomas

i forgot an initial condition, so assume a(0)=0

would be

zip((x,y)->(y-x)^2,[a,b,c],[4,5,6]);

convert(%,`+`);

Thomas

nevermind, setting line thickness higher does the trick.

Thomas

If an exact or  numerical solution can't be found, why not just plot it  and aim with mouse at  points of interest. Coords are shown above.

Thomas

would't it be better to search the min/max of the function without plotting ? In case of failing: As a beginner i would assume that i applied wrong commands to solve the problem. To learn the correct usage of commands is probably easier to understand than analyzing Robert's method.

Use maximize or minimize instead, max/min is for other purposes.

@Robert: Thanks for your input, i'll keep your strategy in mind. Indeed very few info is available about those delayed deqs  (except Axel's link).   All i found were attempts for a numerical solution.

An other idea to solve this bugger could be laplace transform, but i ran into difficulties whith the inverse transformation.

I  know that  f(x)=ax+b is a solution (a,b constants), but are there other ? I'm afraid, Maple has its limits here.

Another one:

e1 := {x1(t), x2(t)};

indets(e1,name);

try DEplot3d in DEtools