# All Questions

18 views

### How to create all possible permutations of length 3 from a set 'A', with some conditions? [on hold]

If we have a set A={a,b,c,d,e}, how to print all possible permutations of length 3, such that, "a" appears before "c", and "d" appears at most once.
33 views

### Solution to y == x^x (1-x)^(1-x) for x

Does anyone have any insight to a symbolic solution to this equation for x in terms of y? Symbolic of any sort, just not numeric. y == x^x (1-x)^(1-x)
18 views

### How to force evaluation of an expression with Part left unnevaluated?

My goal is to minimize a real valued multi-variable function averageFreeEnergyDensity. The function accepts an integer argument ...
26 views

### Graph not drawing after VertexDelete

I'm very new to Mathematica and am currently trying the VertexDelete function, but after using it, my graph isn't drawing. Input: ...
31 views

### Use Do to evaluate an expression over two indices i !=j (over a list of tuples)?

I have an expression of the form: expr1[i_,j_] = Sum[\[Beta][j]*\[Phi][i, j]* C[i] I would like to evaluate this expression over i=1:4, j=1:4 with i!= j. One ...
26 views

### I have trouble in sorting a matrix in wolfram mathematica [duplicate]

I have an array of five elements, I have to make permutations of 3 elements. I have my code: A = {1, 2, 3, 4, 5}; n = Permutations[A, {3}]; Now I have to sort ...
43 views

### Parametrize a circle as a tube?

I have this code: ...
46 views

### How to determine why Solve[] failed?

I don't know what to make of Solve[] failing on this: ...
9 views

### Delete integer cases that contain specified number [duplicate]

I have a sequence generated with this RecurrenceTable function: RecurrenceTable[{a[n + 1] == 7 a[n], a[1] == 3}, a, {n, 1, 10}] and I would like to remove the ...
20 views

### Export to MX seems to corrupt the in-memory Dataset

I have a function that does a large number of calculations (by calling out to other smaller functions), and then builds a large Dataset object. Then I do two ...
129 views

### How is it possible to check if a function is even or odd?

I tried it like this: ...
45 views

### Bug (?) in Mathematica in Derivative of function with Abs [duplicate]

I encountered a weird problem with Derivatives in Mathematica, see the following code: ...
33 views

### How to program efficient undershoot/overshoot

I would like to solve the following boundary value problem for $y(x)$ for a fixed value of $k$ between $0 < k <1$: y'' + \frac{3}{x} y' - y + \frac{3}{2}y^2 - \frac{k}{2}y^3=0 \\ y'(0) = ...
37 views

### Setting an image as the background of a GeoGraphics image

It's easy to set the background of a GeoGraphics image to black, e.g., ...
30 views

### problem with this assignment, can you help? [on hold]

Give approximative values on the all the roots to the equation x = 3sinx. Place the the answers in-growing order
33 views

### Please I need help quickly! [on hold]

Calculate the maximum value M_1 of function f(x, y)=9 log(x^2+2y^2+1)-x^2-y^2 on circle disc with center in origo and radius 4. Calculate the also it maximum the value M_2 who the function suppose on ...
29 views

How can i do in this question? solve the equation system 5x_1-6x_2+4x_3+3x_4=-3 -x_1+x_2+2x_3+3x_4 =6 4x_1-5x_2+6x_3+6x_4=3 -2x_1+2x_2+4x_3+6x_4=12 x1= , s, t x2= , s, t x3= , s, t x4= , ...
64 views

### Encapsulated plot function misbehaves

To insure a collection of plots has identical appearance, the plot command is encapsulated in a function. The results are undesirable. The fiducial plot is ...
45 views

### Recursions in Mathematica

Can anyone explain to me how do I use a recursion, if I don't know the limit. For example, I need the remainder r of the Euclidean algorithm for gcd(a,b) which equals 0. I figured out that the ...
39 views

### Automatically split an expression and use TrigFactor to solve the parts

I want to simplify the following expression: 1/2*(Sqrt[3]*Cos[x]*la - Sin[x]*la - lb + Sqrt[3]*Cos[x+y]*lf - Sin[x+y]*lf) I used ...
22 views

### Constraints for LP [on hold]

Im fairly new to mathematica and I'm writing a minimization problem with constraints: ...
59 views

### ListPlot the results of FindMaximum

I want to plot a list of the form whose elements are of the form {value, {x -> value_x, y -> value_y}} The list generated by FindMaximum applied on ...
87 views

### How to map Unevaluated over a list

I have a list {a1, a2, ...... , an}, in which all as have been initialized to a number. I want to get: ...
57 views

### Improve simulation speed using Compile

I have two square matrices, a hermitian matrix h and an unitary matrix v. I am interested in the following function ...
117 views

### Trigonometric simplification

How can I simplify 1/2 (Sqrt[3] Cos[x] - Sin[x]) in order to get Cos[x + Pi/6] on Mathematica? I saw that Wolfram|Alpha lists ...
56 views

### Numerical integral speed

I have the following code to calculate a numerical integral for any given a, however it takes a very long time, even with adaptivemontecarlo, which is not accurate enough: ...
32 views

### Animating an InterpolationFunction and its integral

I have a list of data that I interpolate (Omega[t]) and animate - it is working fine, but an Integrate over the ...
19 views

### plotting Multiple Functions of graph of trigonometry [on hold]

help me solving this question.i'm using mathematica wolfram version 10.the question is 1 a and 1b.if can, show me the answer in mathematica,i'm quite confused
458 views

### A bug in Integrate

Integrate[(1 + 16 Tan[2 x - y]^2)/(1 + 4 Tan[2 x - y]^2), {x, 0, 2 π}] Mathematica (wrong) output is (tested under versions 8 and 10.0, took ~ 1 minute of CPU ...
27 views

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67 views

### Missing zero in the CoefficientList

The following list has a length only 10 (not 11) CoefficientList[Series[ArcTan[x]/(1-x^2),{x,0,10}],x] {0, 1, 0, 2/3, 0, 13/15, 0, 76/105, 0, 263/315} Should be ...
95 views

### Wrong Limit in Mathematica 10.0.0

Limit[(Log[(3+Sqrt[5])/2]/(2*Log[(1+Sqrt[5])/2]))^(-1-2*n), n -> Infinity] Mathematica (wrong) output: 0 But this is ...
163 views

### Plotting a Hill function [on hold]

I've Just recently gotten this program and cant plot this function, F(X)=1/(1+(X/K)^n) for X=0 to 4 nmol/m^3, K=1 nmol/m^3, F(X)= 0 to 1, and n=1,2,4,8,16 Now I know how to specify the limits and ...
40 views

### How to incorporate the boundary conditions into the differentiation scheme in MMA?

Let that we want to numerically solve the following PDE \label{sde} -r V(S,t)+r S \frac{\partial V(S,t)}{\partial S}+0.5 S^2 \text{sigma}^2 \frac{\partial ^2V(S,t)}{\partial ...
52 views

### Generating and Imaging of the water molecules with Graphics3D

my problem is I don't know how to generate e.g. 20 water molecules: Graphics3D[ Rotate[First@ChemicalData["Water", "MoleculePlot"], 45 Degree, {8, .5, 0}]] ...
47 views

### Wrong Limit with LaguerreL

Limit[(n! LaguerreL[n,-1]/(n^(n+1/4)/Sqrt[2]/E^(n-2 Sqrt[n]+1/2))-1) Sqrt[n], n->∞] Mathematica (wrong) output ...
243 views

### Generate a list of equations of curves and plot them

I want to plot a series of lines. This is how I did it: ...
80 views

### Interpolate/extrapolate a gate charge curve from two different curves

Gate charge measured data. I have gate-charge measurement plots and Excel data for two operating points for a power MOSFET. Vds = 60 V, Id = 50 A Vds = 600 V, Id = 8 mA Can I generate a plot with ...
49 views

### How to disable dynamic update in DynamicModule when certain variable is updated [on hold]

I have a UI with DynamicModules. I have a progress bar, whenever the varibale progress updates, the ...
100 views

### ODE fitting to dataset

So, I have a ODE system, it is a complex biochemical kinetic mechanism with six species changing over time. ...
61 views

### convergence problem - triple integral

I have a problem in convergence ... for i=j=5 is enough to calculate what i want. But for os11[100,5,5]=1.59 ( 1.58 is the real ...
164 views

### Converting multi variable expression into a function

So I have this rather complicated looking expression ...
62 views

### The image turns black when I use the mouse to rotate it

All, This code ...
112 views

### Regime Change Stochastic Process

I would like to simulate an Ito process in which the drift and diffusion terms change after hitting a boundary for the first time. For example, a Geometric Brownian Motion X which has 0 drift and ...
44 views

### Missing definition of some parts of function?

I have: BeginPackage["Test1"]; ClearAll[f]; f::usage = ""; Begin["Private`"]; f[x_AA]:= 1; f[x_BB]:= 2; End[]; EndPackage[]; When later, on a notebook, after ...
71 views

### How do I find the constant term of a multivariate polynomial, when (x^0)(y^0)?

So let's say f[x_,y_]:=(2x+2y+1)^2, when I type Coefficient[f[x,y],x y] I recieve 8. But what can I input to recieve 1, when ...
58 views

### Adding a 3D point using Epilog [on hold]

I am trying to add a point using the Epilog option with ContourPlot3D. ...
47 views

### Fitting data to plot using errors as weights

I have some enzyme kinetics data that I want to fit to the Michaelis-Menten curve in order to obtain the kinetic parameters of the enzyme. Is it meaningful, statistically and functionally speaking, ...
I have a question about how to write the formula in Mathematica. If $w$ is $n$-dimensional vector, with each element as $w_i : i=1,2,3,...n$ and $n$ is symbol, how to write it as vector in ...