# All Questions

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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 ...
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 ...
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 ...
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 ...
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 ...
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 \$...
33 views

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

I have written a very simple nested If as follows ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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: ...
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 ...
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 ...
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:= DSolve[{(1 - x) f'[x] - f[x] == 0, f == 1}, f, x] Out= {{f -> Function[{x}, 1/(-1 + x)]}} as a series ...
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: ...
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 ...
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 ...
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''...
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 ...
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 ...
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 ...
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! ...
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 ...
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 ...
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 ...
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 ...
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/...
306 views

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### 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 ...
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 ...
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: ...
51 views

### Plot with Dsolve

I am trying to plot the solution to the Dolve at a position /. x -> 0 ...
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 <...
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: ...
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 ...
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[]?
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 ...
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]} ...
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. ...
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: ...
112 views

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, ...
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 ...
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 ...
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?