# Items tagged with variablevariable Tagged Items Feed

### Indexed variables in Maple TA?...

February 05 2016
1 4

I try to make a question with an equation with numbered variables. This works fine when evaluating:

y=x1/x2

I need to have the lefthand variable indexed also like this:

y2=x1/x2

When entering y2=x1/x2 as the answer Maple TA won't evaluate it as a correct answer!?

### A problem with a result from solve...

January 11 2016
0 2

I have the following equation:

Diff(W(t), t) = -q*V*(sin(Phi)-sin(Psi[s]))/(2*h*Pi);

I solve it for rhs() = 0:

soln := solve([rhs((2)) = 0, Phi < 2*Pi], [Phi], allsolutions = true,explicit);

This works and I get this result:

Now I want to get the first zeros, which occur for _Z1 and _Z2 equal to 0. So I substitute:

subs(_Z2=0,(3));

and get

In other words, the substitution did not work.

The original problem is embedded in a larger sheet created with Maple 15 and there it does work. It fails on Maple 2015.2. I then pulled out the relevant pieces to make this example demonstrating the problem (see the attached sheet, which has some of my other (unsuccessful) attempts to diagnose what is going on). It seems like the created variables _Z1 and _Z2 are somehow not recognized at all.

The only way I can get the _Z2 terms out is to substitute 2=0. This is really too icky to seriously consider, though.

Anyone has seen this before?

FWIW: Maple 2015.2 on Mac OS X 10.10.5.

Thanks,

Mac Dude

Assumptions_test.mw

### How to extract that fraction?...

January 06 2016
1 2

Hi

i am working on a simple control project.i should make a transfer function from the below equation (as an example):

(s^2*m1+I1*(s^2)*(1/r^2))*x(s)+(-(1/2)*s^2*b*m1-s^2*m1*r-I1*(s^2)*(1/r)+m1*g)*theta(s)+(1/2)*theta(0)*s*b*m1+theta(0)*s*m1*r-x(0)*s*m1+(1/2)*(D(theta))(0)*b*m1+(D(theta))(0)*m1*r-(D(x))(0)*m1+I1*s*theta(0)*(1/r)+I1*(D(theta))(0)*(1/r)-I1*s*x(0)*(1/r^2)-I1*(D(x))(0)*(1/r^2) = 0

in order to make the T.F i have to make " x(s)/theta(s) " on the lhs and put the rest on the rhs. i have no idea how to do so.(the underlined part involves no x(s) and theta(s). obviously a theta(s) will appear on the rhs in the one of the denominators which doesn't matter.)

please help me with this problem.since i don't know what the commands are called in english, i failed in searching for it.

thanks.

### Problem with gamma as variable...

November 21 2015
1 5

 (1)

 (2)

 (3)

 (4)

 (5)

 (6)

how can i solve this problem?

### Indexed variable...

October 19 2015
1 2

How do you check an indexed variable in Maple TA?

For instance the question might be: enter 6x1   (or 6xA1)

I have tried using a Maple-graded question specifying as correct answer 6*x[1]   (or 6*x[A,1]) without any success (works only for 6x).

### Converting a string into a maple variable name...

August 21 2015
1 5

Hi,

Another newbie question...

I have an excel file with lots of named ranges. I can use the ExcelTools WorkbookData command to get a list of all the available named ranges, and then I can assign the contents of each named range to a Maple variable with the Import command.

I'm thinking that there must be an elegant way to create a Maple variable for each string in the list of named ranges and assign it to the contents. Something like looping through each named range in the list, creating a variable of that name, and then assigning the contents of that named range. I hope I'm clear without repeating myself too much.

Am I explaining my need?

Thanks in advance. This looks like a good forum, and I hope to be able to contribute someday.

Mike McDermott

### Function depending on multiple variables - sensiti...

August 02 2015
1 4

I would like to get some sort of table (maybe also a plot) that shows me the effect on the function if I change a variable.

For example, I have f(x,y,z)=x+yz

Now I would like to get a list with the results for f if I run z from, say, -10 to +10.

Is it also possible to do this with all variables at the same time?

July 07 2015
3 9

I can read a .m file written using "save" command, However the variable list (pallete) doesn't get updated. Is there any way to see the list of variables and their values that has been read with "read" command from the .m file?

### Checking linearly dependent of a polynomial on a ...

July 01 2015
0 21

I want to test linearly dependence of a polynomial f on a list of polynomials F by additional condition on parametric coefficients of linear parametric polynomial (linear for variables not parameters). Please note that:

1. The polynomialand the members of are always homogenous in the variables.
2. The coefficients of f, the coefficients of the members of F are all always polynomials in the parameters or contant and the members of N and W are all always polynomials in the parameters.

For example let

and

(a,b,c,d,e,h are parameters and A1,A2,A3 are variables).

If I use PolyLinearCombo(F,f,{A1,A2,A3}) (see http://www.mapleprimes.com/questions/204469-How-Can-I-Find-The-Coefficients-Of-Linear#comment217621)then its output is false,[].

Now we let to condition sets for parameters as the following:

N:=[ebc+ahd]

W:=[a,c]

The elements of N must be zero means that ebc+ahd=0

and the elements of W are non-zero that is a<>0 and c <>0.

Let a=b=c=d=h=1 and e=-1. This specialization satisfy in the above condition sets N and W. By this specialization we have:

and

Now if I use PolyLinearCombo(F,f,{A1,A2,A3}) then its output is true,[-1,1].

By this additional two condition sets I have to check that whether f is linearly independent of F or not. How can I do this without specialization? In fact I want an algorithm that its input is (null condition N, not-null condition W, list of polynomials F, a polynomial f, the set of variables) and its output is true and coefficients if f is linearly dependent of F w.r.t. null and not-null conditions N and W, else its output is false.

If the name of new procedure is ExtPolyLinearCombo and

N:=[ebc+ahd]

W:=[a,c]

I want the output of

ExtPolyLinearCombo(N,W,F,f,{A1,A2,A3}) be true,[coefficients]

Thank you very much in advance.

### parametric function......

June 28 2015
1 19

Hi everyone:

I have two functions in terms of theta variable, how can I expressed function Y(X)?

X :=(theta)->cos(theta)+0.8e-1*cos(3.*theta)

Y :=(theta)->-sin(theta)+0.8e-1*sin(3.*theta)

I will earn Y(X) infact.

Thanks alot...

Mehran.

### Index of variables...

May 26 2015
0 11

Hi all,

I want to define variables with indices, possibly zero. So for example I define mu[01] and mu[10]...

My problem is that mu[01] automatically becomes mu[1] in Maple's output, so that I could not distinguish it from mu[001]...

Is there any way to address it?

Thanks
Manuele

### proving or negating an inequality...

April 01 2015
0 2

Hello. I have an inequality and I need to prove or negate if it is true or false. This inequality has 8 variables. I simplify it and try to see if it is ture or false. I tried "test relation" in maple and it seems I can't say it is always true or false. For some values of the variables it is true and for some others its false. Is there a method I can show if this inequlity is hold under some assumptions? I mean I want to keep some variables as constant and prove it up to a point. My inequlity is below. Thank you for the help in advance.

(P[A]*(p-w)/(1-P[A])-c)*H[A]+(w-P[A]*(p-w)/(1-P[A]))*P[A]*H[A]+w[u]*P[B]*(1-P[A])*H[B] < (P[B]*(p-w)/(1-P[B])-c)*H[B]+(w-P[B]*(p-w)/(1-P[B]))*P[B]*H[B]+w[u]*P[A]*(1-P[B])*H[B]

And this is how it looks on maple:

### Doesn't see a variable when deriving...

March 31 2015
0 1

Hey,

Basically the problem is that when I try to derive a variable L, which is defined by a very big equation, Maple does not do the maple. But if I copy and paste the big equation it calculates everything perfectly. Could I get any insight on why is that?

The copy paste method is very space consuming.

### Multiple Equation solver...

March 08 2015
1 2

Hi,

I am new to Maple and have a problem when solving three equations with three variables. But when  I plug in into solve function then it gives no answer.

eqn1 := 24900 = A*exp(-X*1.293995859*10^22)+A*exp(-Y*1.293995859*10^22)+5852.27;

eqn2 := 6000 = A*exp(-X*1.293995859*10^22)+2422.929937;

eqn3 := 19100 = A*exp(-Y*1.293995859*10^22)+8275.199937;

Variables are [A,X,Y]

### How do I assign an indexed variable λ to change fo...

March 01 2015
1 3

Hi
I have my question makes any sense. I am from Denmark and not used to write math in english.

I have an characteristic matrix with an variable λ that takes on differen values.

How do I write λ in the matrix so Maple knows that when I call out a row with the variable λ in it and asssign

λ to a specific value, Maple changes λ to the specific value.

Example (I was thinking something like this):

A:=Matrix(2,2,[(1-λ_i),2,3,(4-λ_i)])

λ_1:=2

λ_2:=4

A[1],λ_1               (1-2) 2

A[1],λ_2               (1-4) 2

A[2],λ_1               3 (4-2)

A[2],λ_2               3 (4-4)

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