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2
votes
0answers
23 views

What does Sin[2. x] mean?

I am working with a particularly long function that, when I want to evaluate it at a certain $x$, shows: As you can see there are expressions herein of the form Sin[2. x] or Cos[2. x]. What do these ...
0
votes
2answers
24 views

Converting an indefinite integral to definite integral

For example, I have the following integral expression: g[x, y] = Integrate[f[x, y],x] How can I modify the above expression to achieve the following definite ...
0
votes
2answers
22 views

Factoring an arbitrary power from the rest of the expression in an exponential expression

I have the following expression: Exp[r*t*x + e*r*y + t*x*r^2 + y^2*e*Sqrt[r]] I want to choose some arbitrary terms in the power and for example write the ...
3
votes
2answers
36 views

Get parametervalues from ParametricPlot?

From an examplary plot plot = ParametricPlot[{1 Cos[s] , 2 Sin[s]}, {s, 0, 2 Pi}] I know how to get the plotted points ...
2
votes
2answers
44 views

Problems with Integrate in Mathematica

I would like to analytically integrate a function in Mathematica. However, I have found a problem with the final result when I compare it with the numerically integration of the same function. Here it ...
0
votes
0answers
26 views

FindInstance specifying reals increases the time significantly and gives errors

I was wondering if there is any way to put time constraint on FindInstance. My problem is as follows: I want to find two, $2 \times 2$ matricies $A,B$ given $Tr(A)$, $Tr(B)$, $TR(AB)$, $Det(A)$ and $...
1
vote
1answer
33 views
5
votes
2answers
68 views

Can someone tell me what's wrong with this nested IF?

I have written a very simple nested If as follows ...
0
votes
0answers
23 views

Figure out original balance with only the amount of loss and amount of decrease

I'm sure there is an easy solution to this, but I can't remember how to set something like this up. I was thinking a differential equation may be the answer. For context, this relates to stocks, but ...
0
votes
0answers
29 views

How can we tell if an evaluation has corrupted or is still on-going properly?

I was trying to evaluate a NDSolveValue function of mathematica, but it is taking excessively long time (~30 min) now. I am not sure if I shall leave it alone or quit the kernel. Is there a general ...
-1
votes
1answer
45 views

Mathematica 12.0 Dsolve solving 2D diffusion PDE

my friends,i meet some problems,please help me! this is my equation and ic ,bc this is my code .I let some constants R,in,D,F become 1,h become 2,it is convenient to calculate ...
2
votes
3answers
50 views

Simplify expression by a known expression substitution

A bit complex than a similar question, below is a minimal example, eqs1 = a b x'[t]^2 - ac x''[t] eqs2 = x''[t] - b x'[t] - c == 0 I want take ...
3
votes
0answers
49 views

Why does exporting a plot in raster graphics formats add a red background?

Bug introduced in 12.0 or earlier and persisting in 12.3.1 I've generated a Mathematica plot. When I right-click it and save it in a SVG file format like PDF or EPS, it looks great. (Unfortunately, I ...
-1
votes
1answer
50 views

Simplifying multiplies of sums into a single double sum

I have the following expression: Sum[x^n, {n, 1, Infinity}]*Sum[Log[m, x], {m, 2, Infinity}] How can I Force Mathematica to write this expression in the following ...
-1
votes
1answer
55 views

Transforming one exponential expression to multiplication of exponential expressions [duplicate]

I have the following expression: Exp[a * x + b * y + c * z] I want to write this expression as: ...
-1
votes
0answers
28 views

How to point to a specific location in a notebook?

I am writing a very long code and I need to refer to some line of codes in comments to clarify the definitions. Is there any way that I can refer to a line in a Notebook or create a hyperlink to take ...
-1
votes
0answers
24 views

Calculating an unsimplified expression containing derivative of an expression which is substituted instead of a function

I have the following expression: Derivative[0, 1][Integrate[E^(-(n*\[Tau]) - I*k*y*Cosh[\[Tau]])*B[\[Tau]], \[Tau]]][x, y] which is created by substitution of a ...
0
votes
0answers
25 views

Different solutions by AsymptoticDSolveValue with same series centre, once specified as Integer & then as Real

I am trying to solve this first order ode In[1]:= DSolve[{(1 - x) f'[x] - f[x] == 0, f[2] == 1}, f, x] Out[1]= {{f -> Function[{x}, 1/(-1 + x)]}} as a series ...
-1
votes
1answer
25 views

Simplifying an equation in which all the terms are integrals with respect to the same variable

I have an equation in the following form: Integrate[A[x], x] + Integrate[B[x], x] == Integrate[C[x],x] How can I simplify this equation to get: ...
-1
votes
0answers
33 views

Detecting whether a function is initially defined with the form R[x,y] or R[x_,y_], etc

I have a very long code that may have errors in definition of functions and I want to trace these errors. Is there any attribute or function to detect whether a function is initially defined in the ...
-1
votes
2answers
34 views

How to extract entities from TravelDirectionsData?

I am wondering how to extract entities such as states and cities from TravelDistanceData. For example, given the following example from the documentation, how could I extract the states the route goes ...
0
votes
0answers
32 views

Evolution of different species of universe

Very poor knowledge of coding and Numerical solutions. please any body help me. I want to solve the following equations (a'[t])^2=(-κ/3)*(-(φ'[t])^2+V(φ)) a''[t]/a[t]=(-2κ/3)(1+3ω)((-Φ'[t])^2+V(φ)) φ''...
3
votes
1answer
70 views

Stability analysis of coupled ODE's

I'd like to reproduce Panel A of Figure 7 (red curve) of this paper, which represents the steady-state solutions of four coupled ODE's, and verify this claim that the diagonal branch in the Z-shape ...
-1
votes
1answer
32 views

Calculating the derivatives of an integral expression

I have the following function: ee[x, y] = Integrate[x^2 + y^2, x] I want to calculate the derivatives of this function w.r.t x ...
0
votes
0answers
35 views

expression evaluation for Compile[] too time consuming

I need to use Compile[] for a very large expression to be integrated. But for Compile[] the expression has to be evaluated, and this takes endless time. The expression is composed of several functions ...
5
votes
3answers
144 views

How to fill the first region enclose by a self-intersection parametric curve

For an arbitrary self-intersection parametric curve, how to construct the region at its first instersection. Thanks! ...
0
votes
0answers
53 views

How to create a mosaic from characters or small images?

I want to create a piece of art similar to the following two images of Grace Hopper and Bill Gates: I know how to create a word cloud and want to extend this knowledge to make something similar to ...
4
votes
2answers
119 views

How to make c[n_, x_, y_] := ToExpression["p" <> ToString[n]] = {x, y} work?

I am trying to do the following: c[n_, x_, y_] := ToExpression["p" <> ToString[n]] = {x, y} That is: Evaluating ...
2
votes
0answers
41 views

`Correlation[]` returns incorrect result for TransformedDistribution

Here is the code which calculates the Pearson correlation coefficient affect by the Ramp[] function, where c is the general form ...
0
votes
0answers
33 views

Is it possible to run kernel in address space of another process?

Kernel executables seem to be relatively small wrappers around "dynamic link library" that contains all the functionality of the kernel. Is it possible to load the kernel (as a dynamic link ...
-2
votes
0answers
74 views

Code for calculating the number of real roots of the polynomial [closed]

I'm trying to create a code that estimates the number of real roots of a polynomial. General algorithm is outlined in this document: http://stellar.mit.edu/S/course/6/sp10/6.256/courseMaterial/topics/...
9
votes
3answers
306 views

Trying to fit a circle. Data have weights

...
-1
votes
0answers
38 views

What are some good practices for maximizing the wait time for the entity framework? [closed]

I have used this site to learn about how to store entities with many data points such as Cities, AdministrativeDivisions, and Aircraft. I am wondering what are some good guidelines to accelerate the ...
-3
votes
0answers
47 views

How to create a global function? [closed]

I am wondering how to create a global function. I want to build a function that will persist even when Mathematica's kernel is aborted and closed and eventually restarted. I think the answer has ...
-3
votes
1answer
40 views

How to disable legends in GeoListPlot and other geographic functions? [closed]

How can I hide or disable the automatic legend feature of GeoListPlot? I have the following code and results: ...
2
votes
2answers
51 views

Plot with Dsolve

I am trying to plot the solution to the Dolve at a position /. x -> 0 ...
0
votes
0answers
31 views

Simplify including dim of matrix as parameter

I want to check that an identity about matrix is true for all dim n. My idea is to view dim n as a parameter and then Simplify the expression. For example,I hope <...
-2
votes
1answer
43 views

How to color different entities in GeoListPlot different colors? [closed]

I am learning how to use GeoListPlot and am trying to figure out if there is a way to make different entities in a single list different colors. An example of my code so far is: ...
-2
votes
0answers
43 views

How to stop Mathematica from freezing on starting? [closed]

I have a recurring problem where I try to start up Mathematica and it freezes. For every time I try to open Mathematica, it only works about 20% of the time. I have an HP Envy x360 laptop with 32 GB ...
1
vote
0answers
49 views

How to sort functions based on the number of arguments they take? [closed]

How can I find all functions with a certain number of arguments? For example, how can I find all the functions who do not require an argument like RandomReal[]?
4
votes
2answers
130 views

Colouring 3D columns defined by a piecewise function

I am using a piecewise function to define the height of columns. My goal is to make a nice picture that illustrates the different heights of the columns using color. Below in the picture I have ...
-1
votes
0answers
37 views

Substituting a two term expression with two rule on one variable with which each of the rules simplify one of the terms

I have two expressions as follows: r (Sin[t]+Cos[t]) and the rules for simplification are: {x == b + x Cos[t], y == r Sin[t]} ...
0
votes
0answers
47 views

how to find the FWHM of a peak from an equation and not data set? [closed]

I want to find the FWHM of a conductance peak I created on mathematica (see Figure). until now I used the FindMaximum to calculate the max of the peak. ...
0
votes
1answer
52 views

Changing part of the name of the function

Is it possible in Mathematica to replace the part of the name of the function to give the same arguments to another function? In fact, I have a lot of functions with the following name pattern: ...
6
votes
3answers
112 views

How to Add PopupMenu in manipulate?

Manipulate[Column[{ Plot[Sin[a x], {x, 0, Pi}], Plot[Cos[a y], {y, 0, 2*Pi}], Plot[Tan[a z], {z, 0, 3*Pi}]}], {a, 1, 10}] I want to put a popup menu here as Sin, ...
0
votes
1answer
25 views

Discrete Variables cause Step Size Not Real Error in NDSolve

I have, until recently, had great success using discrete variables to manage local changes in the definitions of the derivatives with NDSolve. Now, for reasons I don't entirely understand, this ...
5
votes
2answers
47 views

How to find a list of related functions as mentioned in the documentation center?

How can I list functions related to a specific function in a notebook without opening the documentation center? Sometimes I think I have the right function and have trouble remembering similar ...
0
votes
0answers
41 views

How to get a list of all the Resource Functions on the Wolfram Function Repository? [duplicate]

I would like to find a way to get the name of every single ResourceFunction published on the Wolfram Function Repository. How can I find the names of every single function?
0
votes
0answers
52 views

FindRoot doesn't find root

I am facing a problem that my FindRoot doesn't find the actual roots. I am trying to make a loop that iterates my parameter sets (U0,X0,\Sigma0) to find sets that satisfy some conditions. Here is my ...
3
votes
4answers
98 views

Line integral over a rectangular path

I have a little problem. I need to calculate an line integral of a function on a rectangular oriented closed path. For example I define f[x_,y_]:= x-2y and the ...

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