Thank You for the Notebook.

Sorry, but I don't understand which is the rule of N in the equations. I attach a new Notebook with some additional tests.

You can notice that the formats 0.005 or 5/1000 have a strong impact on the result! And N is a command that impacts only in the representation format of the number. Is it correct?

Than I want to ask you an other question. If now I want to transfer the Prova1 equation from Mathematica to Matlab, I use the package ToMatlab' which writes a .m file with the equation in Matlab format. If then I calculate the expression Prova 1 in Matlab in the same values of the variables, I obtain a different result respect to Mathematica. Do you know the reason?