@Preben Alsholm 

Тhank you 

One more question, please:
Nowhere appears that one_int=0 and two_int=0. So, it all depends on the starting conditions?
If I wanted to get,for example, one_int=5 and two_int=5, then I would have to choose the initial conditions in this way?

Тhank you very much!

But I have a few questions:

1)#one_ and two_int should be functions of X_1 and X_2, not z.

Is it legal?  X_1 and X_2 is constant , which must find.

2) Why do you use "Int" instead of "int" (capital letter), because "int" for computing, "Int" to denote the integral.

3)I have not found in "HELP - fsolve"an example of such designations 

fsolve([one_int,two_int],[-20,19]);

What do these numbers [-20,19]?


thank.