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I'm trying to solve a series of equations and then graph them. I'm trying to solve for the variables involved:

values := solve({eq1, eq2, eq3, eq4, eq5, eq6, eq7, eq8, eq9,

eq10, eq11, eq12, eq13, eq14, eq15, eq16}, {a, b, b, c, d, e, f,

g, h, i, j, k, l, m, n, o, p});


. . . but it gives me this:

Warning, solving for expressions other than names or functions is not recommended. 

values := 

how to access the variable which is currently running in another worksheet

to use for loop to read the Table

when worksheet is evaluating for a very long time, 

expect to read the value Table T in anther worksheet



for i from 1 to nops(polylistresult) do

if i < j then
for j from 1 to nops(polylistresult) do
for k from 1 to nops(polylistresult) do

if j < k then

F := [polylistresult[i], polylistresult[j], polylistresult[k]];
h := function1(F, {x, y, z}, s);
T[h] := [op(T[h]), F];

end if:

end if:

worksheet2 :

for i in indices(T) do

Hi there. 

I'm kind of new to Maple and i'm trying to solve a Linear Algebra problem for my class of Linear Algebra of the course of Physics. Also, my first language is portuguese so forgive for my not-so-perfect english.

I have a (solved) linear system of 7 equations and 12 variables (A, B, C, D, E, F, G, H, I, J, K, L) that is the following:

  • A = 33 - K - L
  • B = 1 + F - J
  • C = -15 - F + J + K + L
  • D = 15 + H - K
  • E = 16 - F - H + J + K
  • G = 34 - H - J - L
  • I = 18 - J - K

Note: I'm using letters (A, B, ..., L) instead of X1X2, ..., X12 because it's easier to write it like this here and because I don't know if the Xn notation is allowed on Maple (i don't think so).

So, the system is possible but undetermined (with 5 degrees of freedom), being F, H, J, K and L the free variables.

Until here, everything's fine. The problem arises when the professor asks us for every solution of the system that satisfies the condition that all the variables (form A to L) are positive integers (A, B, C, D, E, F, G, H, I, J, K, L ϵ IN → natural numbers).

From my understanding, that gives rise to a system of linear inequalities with 12 variables and the following inequalities:

  • A = 33 - K - L > 0
  • B = 1 + F - J > 0
  • C = -15 - F + J + K + L > 0
  • D = 15 + H - K > 0
  • E = 16 - F - H + J + K > 0
  • G = 34 - H - J - L > 0
  • I = 18 - J - K > 0
  • > 0
  • > 0
  • > 0
  • > 0
  • > 0                            (and A,B,C,D,E,F,G,H,I,J,K,L ϵ IN)

After some research, i found that a possible way to solve this type of system of linear inequalities is trough a method of elimination (analog to Gauss-Jordan's elimination method for systems of linear equations) named Fourier-Motzkin. But it's hardwork and i wanted to do it on the computer. After some research, i came across with the following Maple command:


So, I tried to use that command to solve my system, with the following result (or non-result):

LinearMultivariateSystem({F > 0, H > 0, J > 0, K > 0, L > 0, 1+F-J > 0, 15+H-K > 0, 18-J-K > 0, 33-K-L > 0, 34-H-J-L > 0, -15-F+J+K+L > 0, 16-F-H+J+K > 0}, [F, H, J, K, L]);

Error, (in SolveTools:-Inequality:-Piecewise) piecewise takes at least 2 parameters

So, i really need help solving this as the professor told us that the first one to solve would win a book, eheh. I don't know what I'm doing wrong. Maybe this Maple command is not made for 12 variables? Or maybe i'm just writing something on a wrong form. I've never used Maple before so i can be doing something really stupid without knowing it.

I would really apreciate an answer, as my only goal as a future physicist is to unveil the secrets of the Cosmos to us all.

Thank you again.

Miguel Jesus

I have a proc as follows:

for j from 1 to n do;
end do;
end proc;

I chose to use index variables. However when I try to apply a member of the output list as a function of the outermost limit, I do not get any output when I try to evaluate the function. I suspect maple is having trouble with the variables withing the integral. How can I make this work?

I'd like to have a function that I can evaluate:




Dear Maple enthusiasts,

I am unable to find a working method to solve a system of 8 equations, of which 4 are differential equations. The system contains 8 unknown variables and the goal is to find an expression for each of these variables as a function of the time t. I have attached the code of my project at the bottom of this message.

I have tried the following:

  1. Using solve/dsolve to solve all 8 equations at once. This results in Maple eating up all of my memory and never finishing its calculations.
  2. First using solve to solve the 4 non-differential equations so that I get 4 out of 8 variables as a function of the 4 remaining variables. This results in an expression containing RootOf() for each of the 4 veriables I'm solving for, which prevents me from using these expressions in the 4 remaining differential equations.
  3. First using dsolve to solve the differential equations, which gives once again an expression for 4 variables as a function of the 4 remaining variables. I then use solve to solve the 4 remaining equations with the new found expressions. This results in an extremely long solution for each of the variables.

The code below contains the 3rd option I tried.

Any help or suggestions would be greatly appreciated. I have been scratching my head so much that I'm getting bald and whatever I search for on google or in the Maple help, I can't find a good reference to a system of differential equations together with other equations.




PARK - Mixed control



Input parameters



Projected interface area (m²)



Temperature of the process (K)



Densities (kg/m³)

Rho_m:=7000: metal

Rho_s:=2850: slag


Masses (kg)

W_m:=0.5: metal

W_s:=0.075: slag


Mass transfer coefficients (m/s)






Weight percentages in bulk at t=0 (%)






Weight percentages in bulk at equilibrium (%)






Weight percentages at the interface (%)




Atomic weights (g/mol)







Molecular weights (g/mol)






Gas constant (m³*Pa/[K*mol])









4 rate equations











3 mass balance equations









1 local equilibrium equation



Gibbs free energy of the reaction when all of the reactants and products are in their standard states (J/mol). Al and Si activities are in 1 wt pct standard state in liquid Fe. SiO2 and Al2O3 activities are in respect to pure solid state.




Expression of mole fractions as a function of weight percentages (whereby MgO is not taken into account, but instead replaced by CaO ?)

x_Al2O3_i(t):=(Pct_Al2O3_i(t)/MW_Al2O3)/(Pct_Al2O3_i(t)/MW_Al2O3 + Pct_SiO2_i(t)/MW_SiO2 + (100-Pct_SiO2_i(t)-Pct_Al2O3_i(t))/MW_CaO);
x_SiO2_i(t):=(Pct_SiO2_i(t)/MW_SiO2)/(Pct_Al2O3_i(t)/MW_Al2O3 + Pct_SiO2_i(t)/MW_SiO2 + (100-Pct_SiO2_i(t)-Pct_Al2O3_i(t))/MW_CaO);


Activity coefficients

Gamma_Al_Hry:=1: because very low percentage present  during the process (~Henry's law)

Gamma_Si_Hry:=1: because very low percentage present  during the process (~Henry's law)

Gamma_Al2O3_Ra:=1: temporary value!

Gamma_SiO2_Ra:=10^(-4.85279678314968+0.457486603678622*Pct_SiO2_b(t)); very small activity coefficient?


Activities of components



Expressions for the equilibrium constant K












How can I plot a volume (many surfaces) in X,Y, Z axis where X,Y,Z are functions in 4 variables (a,b,c,d), and the domain for the 4 variables are 

-90<=a>=90, -10<=b>=10, -12<=c>=12, -90<=d>=0,


X := proc (a, b, c, d) options operator, arrow; 324.*cos(b)*sin(c)*cos(d)+324.*sin(b)*sin(d)+323.5*cos(b)*sin(c) end procX := proc (a, b, c, d) options operator, arrow; 324.*cos(b)*sin(c)*cos(d)+324.*sin(b)*sin(d)+323.5*cos(b)*sin(c) end proc

Y := proc (a, b, c, d) options operator, arrow; (324*1.*sin(a)*sin(b)*sin(c)+324*1.*cos(a)*cos(c))*cos(d)+(-1)*324.*sin(a)*cos(b)*sin(d)+323.5*sin(a)*sin(b)*sin(c)+323.5*cos(a)*cos(c)-100 end proc

Y := proc (a, b, c, d) options operator, arrow; (324*1.*sin(a)*sin(b)*sin(c)+324*1.*cos(a)*cos(c))*cos(d)+(-1)*324.*sin(a)*cos(b)*sin(d)+323.5*sin(a)*sin(b)*sin(c)+323.5*cos(a)*cos(c)-100 end proc

Z := proc (a, b, c, d) options operator, arrow; (324*cos(a)*sin(b)*sin(c)-324*sin(a)*cos(c))*cos(d)-324*cos(a)*cos(b)*sin(d)+323.5*cos(a)*sin(b)*sin(c)+(-1)*323.5*sin(a)*cos(c)+150 end proc

Z := proc (a, b, c, d) options operator, arrow; (324*cos(a)*sin(b)*sin(c)-324*sin(a)*cos(c))*cos(d)-324*cos(a)*cos(b)*sin(d)+323.5*cos(a)*sin(b)*sin(c)+(-1)*323.5*sin(a)*cos(c)+150 end proc



I want to calculate a new position (X,Y,Z) for a cartesian model with 3 points (dX,dY,dZ) but  I got a problem, my point is a parameters, so I can't change it in the simulation in real time with a Input signal on the components. Does It exist a solution for convert a parameters to a variable to get a Input signal?

Exemple of my calcul:

eq:= [x(t)= dx+sin(dy/dz), y(t)=dy+20,z(t)=dz]




I am new in Maple and I'm trying to get functions from system of equations.

Constants are defined in line 4 and equations are:

eq1 := E2 = fE2(1+(KaE2+Ca)/(1+KaE2*fE2+KaT*fT+KaDHT*fDHT)+KsE2*Cshbg/(1+KsE2*fE2+KsT*fT+KsDHT*fDHT))

eq2 := T = fT(1+KaT*Ca/(1+KaE2*fE2+KaT*fT+KaDHT*fDHT)+KsT*Cshbg/(1+KsE2*fE2+KsT*fT+KsDHT*fDHT))

eq3 := DHT = fDHT(1+KaDHT*Ca/(1+KaE2*fE2+KaT*fT+KaDHT*fDHT)+KsDHT*Cshbg/(1+KsE2*fE2+KsT*fT+KsDHT*fDHT))

KsT = 0.10e11; KaT = 4.6*0.10e6; KsE2 = 3.14*0.10e10; KaE2 = 4.21*0.10e6; KsDHT = 3*0.10e6; KaDHT = 3.5*0.10e6;

fT, fE2 and fDHT are variables, not functions (i.e. fT is not f(T) ) and I am trying to get fT=f(E2,T,DHT,Ca,Cshbg), fE2=f(E2,T,DHT,Ca,Cshbg) and fDHT=f(E2,T,DHT,Ca,Cshbg).

When I type:

eliminate({eq1, eq2, eq3}, {fE2, fT, fDHT})

Maple gives me a blank field. No error, no other comment.

I have no idea where I'm making mistakes.

Any suggestion is appreciated.


Thanks in advance.

      (in sum) summation variable previously assigned, second argument

gives an error, since k is not free. Fine. No problem. But add() has no problem with an assigned variable:


and seq() has no problem either


It is confusing when learning Maple since it does not seem to behave the same way in all its functions. What is the reason for this design? 

Hello, everyone.

There are two variables: n1 and n2, how to define n1+n2=1 (not n1:=1-n2).



I'm having some trouble maybe someone can point out my error please. I'm using the Maple 18 worksheet to try some basic linear equations. The trouble is in the last step.


1.) I start with 2 ordered pairs (2, 14) and (14,18)

Then I put in my formula to discover the slope. I confirm it looks correct in the Variables window.

m := (y2-y1)/(x2-x1);


2.)  Next I input the values for my ordered pairs. I also confirm thru the Variables window.

x1 := 2;

y1 := 14;

x2 := 3;

y2 := 18;


3.) Now I can type m and expect to get an answer to what my slope is.


4.) Now I want Slope/Intercept form of y=mx+b. When I put in the formula y-y1=m(x-x1) i get a strange result


When I execute this formula, the result is y-14=4. (or thru context menu I tell it to solve for y, then I get y=18)


When I manually input the values, the output is y-14=4x-8 (or thru context menu I tell it to solve for y, then I get y=4x+6)

y-14 = 4*(x-2)




Why is my equation (y-y1=m(x-x1)) not executing properly?

This has been buggin me all day, but if i define a variable with an expresion say "a:=3 x+5" and i then want to assign this expression to a function like so "f:=x->a". if i then call f(7), maple return with "3 x+5" so just returning the value of a without substituting x with 7.

Is there any way in which i can define a function this way?

I am new user of Maple. I have an expression like f(x,y)/g(x,y) and I want to have Maple name f(x,y) as something simple like "h" so that later equations write h/g(x,y) instead of the complete f(x,y)/g(x,y), and also to be able to simplify other equations in terms of h.

For example, a=(x+1)(y-5)^2/(x+y-3). Can I get Maple to let h=(x+1)(y-5)^2, so that I get h/(x+y-3) when I ask for a?

Sorry if this question is basic (and my math terminology incorrect), but I have been trying for a while.


sometimes I observe extreme delays when simply entering a variable name like fooBar; right after starting a Maple session. This happens when the current directory contains a file with that name, because Maple automatically loads this file.

For example, if I create an empty file fooBar.m and start a Maple session,

> fooBar;
Error, `./fooBar.m` is an incorrect or outdated .m file

raises an error. More often however, I have some huge Maple files in the working directory and whenever I use (by chance) a variable name in the Maple session that matches a filename, Maple tries to load the corresponding file.

Is there a documentation of this behaviour and a possibility to stop this automatic loading of files?



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