Questions tagged [variable]

Questions on the use or manipulation of Mathematica variables (i.e. names associated with a changeable value). Use [variable-definitions] or [assignment] for questions on variable context localization, or assignment.

202 questions
64 views

How to read in and assign values from a txt file?

I have a text file that I would like to import into Mathematica - after searching around the internet, I can't seem to find any pages that explain how to do this: The text file containes these four ...
53 views

Table and FindRoot of a 2 variable function of x and t : cos(x + 3t)

I am trying implement mathematica commands: Table and FindRoot, of a 2 variable function <...
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Problem with fitting

So I have a very simple question related to a simple topic, but also directly related to a fitting problem. I see that my question is related to this question but I don't manage to make the bridge ...
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I have ...
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Five equations to solve 6-variables question, is it possible?

I was given a task to find the value of variable a,b,c,d,e and f. But I'm not sure it is even possible, given that only 5 equations are available. Can anybody point out how to solve these: ...
34 views

How to use a table with two variables as the values for a function with two variables (x and y)? [duplicate]

I'm sorry if this is a dumb question. I am a student and have 0 prior experience with Mathematica or any sort of coding and I have looked at various resources trying to figure it out myself but still ...
28 views

Bounding Solve results to named variables

How can i bound results of my Solve function to variables properly? This metod works but causes unexpected troubles i struggle to resolve ...
128 views

How do I create a variable that uses I?

I'm planning on working with a set of non-linear differential equations. A few of the equations look like: Mathematica tells me that I is protected. Is there any ...
34 views

Simple question about variables into functions

Im trying to write a very simple code that will solve an equation. total = 800; side1 = x; side2 = total - 2 x; f[x_] := side1*side2 f[x] f'[x] Solve[f'[x]==0] ...
22 views

How to define a function, that generates matrix of variables, which can be later used in Reduce?

My goal is to generate matrices, on which I will put different constraints in Reduce funcion, e.g.: ...
67 views

Separating variables in a set of equations

I have a very large set of equations eqs with variables denoted by capital letters like PVA, QA, etc. and small letters like ica[1,2], tr[2,3] etc. And I have ...
45 views

Apply different PlotStyles to functions with functions as variable [closed]

I have a function func[expr,var] with which I want to plot the list expr[var] and have different styles applied to it. When ...
45 views

Rearranging similar terms in an equation

In a piece of code I am writing, I run into an equation of the form ...
51 views

How to show the answer in terms of another variable

if we have A = 1; B = 44 + 1 output :: B = 45 how we can show B like this output :: B = 44 + A
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Possible to solve this function?

I have this function: Emax[T_, d_] := -(1/2) + d + d/(-1 + E^(d/T)) - 1/2 Coth[1/(2 T)]; All I want is to transform this Function so I get: ...
54 views

Showing variable values on a 3D Plot

I am running a 3D plot a 100 times to show the dynamics of two undetermined variables (cM and cR) for a 100 values of ...
25 views

Extract and name PNG's from loops [duplicate]

I want to extract PNG files and name them depending on the dummy variable of a loop. For example, starting from ...
37 views

matrix perturbation general formula with random values

Is there a way to generate an arbitrary-sized diagonal matrix of variables, not numbers, in mathematica? Probably unnecessary context: For a research question I'm pursuing, I want to find general ...
37 views

Use Solve for two Functions to find 1 common Variable

I have 2 functions that look like this: F[t_,d_]:= 10+t+2d G[t_,d_]:= 5+t+d I'd like to solve this in such a way to know for which t both Function have the Same value. I assume that this won't be ...
322 views

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Use Manipulate for a global variable

I do have a global variable called w1, which is used as a factor in a dataset, however I want to make this factor dynamic. ...
51 views

How can I evaluate a function using the results of Reduce?

Can I use the output of reduce to define a variable in a function definition? In other words, can I somehow skip the step where I manually enter t:=2? ...
39 views

assigning numerical values to variable

I have a csv data file, has two columns of data. First column denotes time (t) and the corresponding value in the second column is flow rate (f). I would like to assign these values to an array f[t], ...
150 views

What are the valid symbol names for packages?

Regarding to the message: ...