All Questions

75 views

A simple question about replaceall and plotting

I was trying to replicate the picture produced on the following Wikipedia page: https://en.wikipedia.org/wiki/Evolute with the astroid emerging as the envelope of normals to the ellipse. I ran into ...
50 views

Riemann Zeta function definition was expanded by Euler with an infinite product series [duplicate]

The Euler infinite product series definition for Riemann's zeta function requires that Mathematica use all prime numbers in the product series. Can anyone help me with the code that will give a ...
32 views

Substitute arguments before evaluating variables in Block [duplicate]

Suppose I have f = x^2; mod[x_] := Module[{}, f] Then mod[3] returns x^2. Is there any way to tell Mathematica to treat the "x" inside of f as the same "x" as ...
262 views

why MatchQ is fast and Replace slow?

Consider a large expression, say a polynomial with 25 terms expr=Product[Unique["a"],{i,1,25}]; to which you apply the following replacement rule: ...
41 views

How to set Ticks for an AngularGauge?

How do you set custom ticks on an AngularGauge. ...
108 views

Color a single contour from a ListContourPlot3D using values from a list

I want to map an electrostatic potential onto a density map. How can I color a single contour from a ListContourPlot3D using the values from another list? Make ...
53 views

Plotting a function based on complicated integral

I have this function : f[Lambda_] := K Integrate[x Exp[- x^2-Lambda x] HypergeometricU[-Lambda,1/2,(x+ Lambda/2+2)^2],{x,0,Infinity}]; where ...
34 views

Coding help on plotting two functions [closed]

I am trying to plot two functions. Trying hard, but not able to see what is wrong in the function definitions. ...
240 views

Rotating an Interpolating Function

I have used the following code to generate eigenfunctions of a PDE: ...
21 views

N[variable,2] displays 6 digits [duplicate]

The following code doesn't behave as I expect. Rather than getting 2 digits upon varying r, I get the default value of 6 digits. What's up? ...
105 views

Out of range red glow on inter-dependant sliders in manipulate

In manipulate, I need to define two sliders : one basic slider, and a second one for which the end value depends on the current value selected on the first slider. How can I achieve this in ...
237 views

Combinations of multiple matching patterns

I wonder if there is any nice way to combine DownValues (or any other suitable rule-/pattern-/function -based Mathematica construct) when multiple patterns match an expression. Let me explain what I ...
117 views

Efficiently generating tuples with Outer

I'm trying to efficiently generate tuples of lists of objects that satisfy a given criterion. The similar questions that I have found on this website end up finding a specific workaround for the given ...
43 views

using Map to apply 2 lists to the LCM function - help [duplicate]

I have 2 lists of numbers and I want to quickly compute the array of answers to the LCM function for the 2 lists and a 3rd static number. I tried the following ...
30 views

How to simplify a ratio [closed]

I have a ration of the form $\frac{p^2}{(p^2+1)^2}$. I can simplify it using $p^2=p^2+1-1$, and to get $\frac{p^2}{(p^2+1)^2}=\frac{1}{p^2+1}-\frac{1}{(p^2+1)^2}$. How can I create the rule to do it ...
77 views

Euler-Maclaurin summation

I want to compute asymptotic approximations to partial sum of harmonic series in Mathematica, using Euler-Maclaurin summation formula. ...
33 views

Reverse element in nested list [closed]

Suppose I have a list as the following: list={{1,9},{7,0},{8,6}....} How can I reverse the element in such way that the output would be the following: ...
26 views

Unstable command line startup time [closed]

I installed Mathematica in an Ubuntu machine, and the start up time in command line is very unstable. Some times open instantly, another times get 40 seconds to open it. I'm using no interface, just ...
50 views

Weird behaviour for a vector InterpolatingFunction inside an NDSolve

I have run into some weird behaviour on the part of NDSolve which I find pretty bizarre and which I would like to understand better. Suppose, for the sake of ...
93 views

NDSolve memory usage

I am trying to solve numerically a system of linear ODEs with some quickly varying driving functions. The basic command is: ...
105 views

Linear fit with conditional noise distribution

I need to fit a linear model of the form $y_i = a · x_i + b + e_i$. The $e_i$ are independent noise from a distribution that depends on $x$ as well as on global parameters of the data; however, the ...
24 views

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65 views

Difference between two Listplots [closed]

this is a simple question, and excuse me if it's already been answered; I searched around and couldn't find anything. I have two listplots, both along the same number of x data points, but with ...
22 views

Multivariables series expansion up to some power of all the variables [duplicate]

I have a function f[x, y, z] that I would like to expand up to a given power of xyz. For now, I am using ...
29 views

Nonlinear coefficients are not supported in this version of NDSolve [duplicate]

Thanks to the answers in other questions, I am aware of the fact that NDSolve produces Nonlinear coefficients are not supported in this version of NDSolve when some boundary conditions are ...
63 views

Product derivative on derivative [closed]

this is a silly question, probably. How to product derivative on derivative in Mathematica. I mean for example how to achieve this result: Just more explanation. I need this for solving task with ...
32 views

What do I need to know about simplifying expressions involving Symbolic Tensors?

I want to use Mathematica to show that the inner product of a vector with itself is equal to the square of its norm. This is what I tried: ...
77 views

PlotMarkers shadows the settings by Style

The code below gives color-varying points with explicit Style wrappers: ...
49 views

382 views

Improving visibility of text in scanned image

I have as example the image below and would like to improve it in such a way that mainly the text is visible and the noisy background is removed. How can that be done best?
99 views

Phase Portrait to Differential Equation [closed]

I posted this question on Math.SE and have received a satisfactory answer in the context of that website. I am re-posting it here to get input from Mathematica users. Why would I receive a different ...
77 views

Using functions in Solve [closed]

i wanted to calculate the real roots of a function. To my knowledge the function i defined has no real roots, so i expected an emptyset, but instead i got some Root[...#..] answers by Mathematica. ...
105 views

Plotting a Double Sum

I am attempting to plot a graph of a function that is the absolute value of the double sum of an exponential function, and I keep getting errors. Here is the code: ...
36 views

How to modify wrong time zone in a Date object?

How can one modify the wrong time zone in a DateObject, without a conversion? Can one manipulate the TimeZone directly without having the numerical value of the time changing?
59 views

Unexpected behavior of Set [closed]

Set doesn't work in some conditions. ...
52 views

$4$-d system of second order PDEs

I have a $4$-dimensional nonlinear system of second order PDEs with periodic boundary conditions. Let $y(t,x)=(y_1(t,x),...,y_4(t,x))$ with $t \in \mathbb{R}$ and $x \in [0,1]$ then the system is ...
31 views

How to fit the data comes from the table into a function of x so that I can plot Two functions using TWO Y aix in one figure [closed]

I plot data results from the package GWR to find the invers function of Laplace transformed fn. How can I fit this data into a function so that I can plot it in using TWO Y- ...
40 views

How can I change the autonumbering criterion?

In a notebook I have three cells whose format is DisplayFormulaNumbered: a=1 b=2 c=3 and in a text cell I refer to them respectively as (1) (2) (3), where (1) ...
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48 views

Personal Reminder with Speak capability repeats multiple times

I am trying to create a personal reminder for myself using the Speak function in Mathematica hoping that the computer speaks the task only once at the designated time. However, I have found that the ...
38 views

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44 views

ArXiv queries not working with ServiceConnect [closed]

Support for interactive with ArXiv's apis was added in 10.2, but now as of 10.3.1 the most basic example in the documentation seems to fail: Is this a known issue/bug, or am I doing it wrong?
42 views

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44 views

Transposing a table [closed]

I created this table so that it is a collection of 5 different functions that I need. It outputs the values that I want, however, I cannot figure out how to get the orientation right. I would like to ...
96 views

Find a family of curves

I have a diagram with seven curves (each with a different parameter). My goal is to find a function for the family of curves (i.e. a single function not just for the seven parameters, but for all ...
45 views

Create an indexed list of functions [duplicate]

I am trying to use a Table to create the following object: {f[#,1]&,f[#,2],f[#,3]} The obvious doesn't work, ...
51 views

Finding a vector many times

I have a vector matrix of profits say prof= {{1, 1, 1, 1, 1}, {2, 2, 2, 2, 2}, {3, 3, 3, 3, 3}, {4, 4, 4, 4, 4}, {5, 5, 5, 5, 5}}; I have a "terminal value ...
67 views

Table of Buttons [duplicate]

What's the correct way to form a table of buttons in which each action depends on the index in the table? E.g., I want to get {Button[1,f[1]],Button[2,f[2]]} ...