@abbeykabir Sorry, I don't understand it. Maybe someone else will.

Here's the only thing that I can think of to do with these 11 complex numbers: They can be plotted simply as points in the complex plane, with the numerator roots in one color and the denominator roots in another color.

@Gruyere I've noticed that you've spelled the variable name both broSet and brotSet, although it is consistently brotSet in "the entire code". If it is actually not consistent, that would cause the problem.

I am assuming that you are translating the problem statement from another language into English. But I am completely baffled by the translation. Try posting the problem statement in its original langiage.

@Oxtoto612 The circle-r is some bad character encoding for a right arrow, the right arrow meaning "approaches" in the sense of a limit. The expression in question means, in Maplese, limit(T(z)^r, r= infinity) = 0.

For some reason, this Question does not appear on the Active Conversations list (even in the long version of the list). This must be a bug in the MaplePrimes software. Maybe this Reply will cause it to appear.

Regarding your question: The numerator has 5 roots and the denominator has 6 roots. So now we have 11 complex numbers (one of which is also real, but that's irrelevant). What do you want to do with them? "Parametric plot" doesn't make sense in this context.

@Kitonum Yes, certainly simplify, expand, and combine slow things down significantly. I was just making two simple modifications to the existing code to make it work. All rational arithmetic and is done automatically, and procedure sqrt always simplifies square roots of perfect squares, so the types in your example work. But combinations of square roots that simplify to rationals are not necessarily done automatically (and, unfortunately, they aren't even necessarily done by simplify).

Do not remove the original question. Instead create a new question.

Do not remove the original question! Make a new question instead.

Please don't edit out the question! People refer to these questions and answers for years to come. If you edit out the question, they can't. So please put it back.

@Markiyan Hirnyk I'll remember that sacred cow saying. Another saying is "The perfect is the enemy of the good."

One vote up is mine.

@J4James This system is very close to the extensively studied Lorenz system. Indeed, it is so close that I think that the OP made a typo. The only difference in the Lorenz system is that the second equation has 28-z(t) where the OP has 28-x(t).

@mohammad2232 The command implicitdiff(..., y, x, x) produces the second derivative of y with respect to x (d^2y/dx^2). The notation (-cos(t)/sin(t))' indicates the derivative with respect to t of the derivative of y with respect to x. In differential notation it would be (d/dt) (dy/dx) or perhaps d^2y/dx/dt. To get d^2y/dx^2, you need to divide this by dx/dt, or just let implicitdiff do it all as one computation.

@Carl Love Axel's method of changing the numeric integration method is much faster than mine.

@PunkRediska Your expressions are too long for me to cut-and-paste. Would you please upload a worksheet with the definitions of the four variables Vx, Vy, xxx, yyy? The worksheet doesn't need to have anything else, if that helps.

A quick glance indicates to me that your functions have an extreme number of points of non-differentiability.

To get any help, you'll need to post the code for your preliminary steps such as Vx, Vy, xxx, and yyy.