## Sergio Parreiras

Dr. Sergio Parreiras

## 135 Reputation

17 years, 165 days
UNC Chapel Hill
Associate Professor

## Syntax errors...

First: D is a protected variable, you have to use another name. Say use d2 instead of D. Second: it is solve and not Solve, there is no capitalization. Third: do you want: all solutions? including complex numbers? or only real solutions? Fourth and last:  I suspect that there are errors in the system you entered: D shows up only in one equation, you do not have D in another equation or inequality besides D-a-c-e-i=0. So why don't you remove both this equality and the variable D?

## Maple vs Mathematica...

I use both Maple and Mathematica.

1. I mostly use Mathematica for my classes as my University has a license for Mathematica for all students but our Maple license only covers faculty.
2. In my research I use mostly Maple because for: solving systems of differential equations and for solving systems of polynomial equations, Maple seems to be faster and better.
3. However, for plotting I still prefer Mathematica. The latest version of Maple finally give us something similar to Mathematica's RegionPlot but Mathematica ability to plot regions that satisfy any system of inequalities, equalities involving boolean operations still seems superior to Maple's capabilities.
4. One think in Maple that I really hate is its' poor capability of exporting LaTeX. It shows that Maplesoft has not really invested seriously in making this feature to work for Maple users. The LaTeX code generated by Maple has lots of Maple own's LaTeX commands. So we are not really exporting some LaTeX file that we could incorporate in our own LaTeX document. Maple ought to have an option to export pure LaTeX/AMSTeX code without MapleTeX gibberish commands.

Sergio Parreiras

Associate Professor of Economics, UNC-CH

## there is a common denominator...

@Carl Love , sorry the expression above was the result of simplify symbolic so it may not easy to see

(perhaps an imperfect copy & paste)  but part of the original expression is:

so here one can here clearly see that,

is indeed a common denominator which simplify/symbolic is not able to isolate.

## there is a common denominator...

@Carl Love , sorry the expression above was the result of simplify symbolic so it may not easy to see

(perhaps an imperfect copy & paste)  but part of the original expression is:

so here one can here clearly see that,

is indeed a common denominator which simplify/symbolic is not able to isolate.

## thanks and follow-up...

simplify symbolic works well but unlike the usual simplify it is not collecting the common denominators, is there a way to force Maple to place everything under one denominator?  SO I can the focus on simplifying the numerator by hand?The ugly case I am dealing is silar to the below (notice that all denominators are identical but Maple would not bring it to the same denominator.

## thanks and follow-up...

simplify symbolic works well but unlike the usual simplify it is not collecting the common denominators, is there a way to force Maple to place everything under one denominator?  SO I can the focus on simplifying the numerator by hand?The ugly case I am dealing is silar to the below (notice that all denominators are identical but Maple would not bring it to the same denominator.

## Maple 17 maybe the way....

@Carl Love Thanks a lot for the feedback. I will try to install Maple 17.

## fsolve can look in a range...

@tevez32 please look at my edited answer above. fsolve can search for the solution for x in [0,Pi/2] and y in [0,Pi/2].

The answers for l2 is still negative, if you require l2 = 0 .. infinity, fsolve gives you no answer.

Perhaps the equations are not correct?

## fsolve can look in a range...

@tevez32 please look at my edited answer above. fsolve can search for the solution for x in [0,Pi/2] and y in [0,Pi/2].

The answers for l2 is still negative, if you require l2 = 0 .. infinity, fsolve gives you no answer.

Perhaps the equations are not correct?

## It is not clear what is being asked....

Being more specific sometimes helps...

## my system...

Sometimes Maple solves a smaller version i:=4 very fast (2000 or 5000 seconds) but sometimes even the smaller version runs forever and ever - even if I askf or the same amount of resources: memory, CPU time, swap memory, processors! I am starting to suspect that are some gremlins at work...

G3.txt

## my system...

Sometimes Maple solves a smaller version i:=4 very fast (2000 or 5000 seconds) but sometimes even the smaller version runs forever and ever - even if I askf or the same amount of resources: memory, CPU time, swap memory, processors! I am starting to suspect that are some gremlins at work...

G3.txt

## try SolveTools[Parametric] instead of s...

@williamov  try SolveTools[Parametric]  instead of solve. In this case both give the same answer but if you are using polynomials, I think Parametric may perform better.

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