# All Questions

62 views

### How can I put the results of TrigFactor function into a more convenient form?

a1 D11 Cos[n x] + a0 a1 D11 Cos[n x] + 1/2 a1 a3 D11 Cos[n x] + 1/2 a2 a4 D11 Cos[n x] I have a large trigonometric expression. Can I factor out different ...
40 views

### How to add a positive definiteness of a unsymmetric matrix as a constraint to a Findminimum problem

The problem is I have a function which has 33 variables, and which to minimize it in a given set of contraints. I have also a matrix consisting of these 33 variables. The condition is that this matrix ...
125 views

### Projectile motion in Mathematica using Euler's method [duplicate]

I need to write the equations of a ball in projectile motion (ignoring air friction) with an initial velocity of 40 m/s at an angle of 40° with respect to the horizontal. Specifically, I need to ...
79 views

### How to plot and visualize a single linear vector in 3D? [closed]

I have a vector (in physic) designated as F1=250cos(60)i+250cos(60)j+250cos(45)k, and i would like to see it in a 3D graphic with the axis centered at the origin, after what i would include other ...
146 views

### How to construct a linear feedback shift register

Are there any posts regarding the construction of a LFSR (Linear Feedback Shift Register) in Mathematica? I can't seem to find any and I am not sure how I would construct one.
66 views

### Determination of Ricci tensor and Scalar curvature from veirbeins

Consider the following metric: $ds^2=h(r)\bigg(dr^2+r^2\big(d\theta^2+\sin^2\theta ~d\phi^2+(d\psi+\cos\theta ~d\phi)^2\big)\bigg)$ We can try to compute the Ricci scalar of this metric by using ...
115 views

### Non linear model fit

I need to fit this, but for some reason I cannot... data = {{0.617,0.8}, {0.605,0.6}, {0.5997,0.4}, {0.5972,0.2}, {0.5985,0.1}}; soln = NonlinearModelFit[data, {y - 2478.82*wlog[kc + 1]}, {y,w,k}, ...
104 views

### Estimating Parameters of a Custom Distribution

The problem is I can not get estimation of parameters of any custom probability distribution (distributions are not built in Mathematica), here is an example: First: I entered random numbers of ...
155 views

### Generate Matlab figure

I am currently working on a project. Because of lack of communication between my team mates and I, I did most of the work (and the graphical figures) in mathematica. Now, I have to pass all the ...
68 views

### Get all variables in an expression with Variables[]

"\[Phi]" <> "1"; Variables[%] Exp["\[Phi]" <> "1"]; Variables[%] Exp[Subscript[\[Phi], 1]]; Variables[%] Say I have lots of variables used for ...
119 views

### Suppressing reduction in fraction box size in multi-level fractions [duplicate]

Mathematica display complex fractions like this, the second x look smaller, I want it look like this, how can I get it in Mathematica?
165 views

### eigenvector bug also for matrix with numeric value [closed]

I just realize that probably there is a bug also in calculating the eigenvector of a matrix with numeric values (see here for bug in eigenvector calculation with symbolic value). In particular in my ...
238 views

### Show Progressbar after pressing a button

I've recently struggling with Buttons. So I understand Buttons have the form Button["text",action]. Now I want the action to be ...
138 views

### How to solve this nonlinear 2 by 2 equations?

I have a equation (x^2 + q1^2 - y^2)/2*(x + q1 - y) + (1 - 2*a)*q + 2*F = 2*(1 - a)*c[q] in q(variable) with parameters q1,a,F and function c(in variable q also, and I define it outside Solve so I can ...
162 views

### Why is 1. x (Times[1., x]) not simplified to x?

This is maybe a silly question, but I could not think of any logical reason why it is not simplified automatically. I was working with a big linear equation system with some constrained inequalities ...
130 views

### Defining new Cellular Automata rule [closed]

I want to define a new Cellular Automata rule as follows {{1, _, 1} -> 0, {1, _, 0} -> 1, {0, _, 1} -> 1, {0, _, 0} -> 0} where _ represents Blank ...
285 views

### How to use FindRoot` to solve an equation containing a parameter?

I'm trying to derive some of the results of the following paper: Electrodynamics of semiconductor-coated noble metal nanoshells, JT Manassah - Physical Review A In the paper there is matrix \$\mathbf ...
87 views

### Why does Fourier give a large error in MachinePrecision?

Consider this code: ...
40 views

### save all inputs as list [duplicate]

I received three results of calculations: {k->0.190729} {k->0.197575} {k->0.249319} Could you help me write the results in the following form: ...
174 views

### Fraction of fibers that have failed

I have the following to set into mathematica. Assume a stress(sigma) applied on a specimen which has a number of fibers within it. All fibers that have a strength less than the applied stress should ...
75 views

### nested series expansion

I have to invert the following matrix in which the functions U[t,x,y,r] and K[t,x,y,r] and all their derivatives are "small"; ...
122 views

### A problem with set values

The following code is just an example to clearly explain my problem. Assume that : ...
147 views

### How to do symbolic definite integral without copy and paste the intermediate results?

I am do a symbolic definite integral, I am doing it like this: Integrate[1/Sqrt[(ϵ + u)^2 + Δ^2], ϵ] // FullSimplify It gives an output: ...
131 views

### The precision of the number

I have problem in Mathematica with unnecessary rounding which is caused by high precision. For example I have value a = 2.052685846*10^-1865, when I make ...
142 views

### How can I obtain more significant digits? [duplicate]

I type f1[x_] := 12 x^5 - 975 x^4 + 28000 x^3 - 345000 x^2 + 1800000 x N[f1[15.5], 15] and obtain 3.74112*10^6 BUT It´s not true!!! the result is larger than ...
1k views

### How can I draw this particular phase diagram in Mathematica? [duplicate]

Sketch the phase diagram for systems with the following velocity functions where a and b are constants with ...
264 views

### Using an image as a moving object in an animation

I have following animation: ...
63 views

### Mapping a function of two arguments where the 2nd arg has a fixed value

I create three random images: i1 = Image[RandomReal[1, {8, 12, 3}]]; i2 = Image[RandomReal[1, {8, 12, 3}]]; i3 = Image[RandomReal[1, {8, 12, 3}]]; I can scale a ...
134 views

### Explicit, closed formula for recursive integral as a function of the recursive parameter

This is a follow-up of this question/answer. I'm working on a recursive integral more complicated than the one on the linked question, but this one can be used as an example. I would like to obtain ...
211 views

### Passing lists to functions in a manner that works like pass-by-reference in other languages?

Is it possible to use a list as a variable, i.e., to pass it by reference to a function? In particular, I have a two-dimensional array and a function to get one element specified by its position: ...
156 views

### Speed up manipulate by exporting each step as an image

Consider a manipulate function such as: ...
99 views

### Gaps in plots of equation solution from parameter

I'm trying to plot solution of system of equations as a function of parameter ...
175 views

### How do I include both text and variables in Input[ ]?

I want to prompt a user to input an answer to a question. I want the question that pops up to have both text and numbers or strings. For example, if I ask the user to give a name to something in the ...
114 views

### Can I force a function to quit and return some value after a certain amount of time has passed during its evaluation?

Imagine I provide some random input to function like FindInstance[], and I observe that, despite the existence of good solutions, the function will, with some ...
1k views

### integration on real domain only!

i am trying to integrate a real valued function. For some reason, Mathematica gives an answer in the complex domain. I'd be grateful for your answers. Here is the integral: ...
859 views

### How to show legend in a combined plot of many lists,

I am having trouble with adding a legend to a plot. The example I discuss here is simpler than my real problem, but describes it well. I have a vector, called X with dimensions (100 x 6). I use the ...
618 views

### Integral with the derivative of Dirac delta does not evaluate correctly?

Integrate[DiracDelta'[y - z] DiracDelta[x - z], {z, -Infinity, Infinity}, Assumptions -> x \[Element] Reals && x \[Element] Reals]
115 views

### Good Introduction / Tutorial to Mathematica **Books** [duplicate]

Possible Duplicate: Where can I find examples of good Mathematica programming practice? I'm a high school senior and am using Mathematica for a research project. However, I find it a bit ...
960 views

### How to get data from For loops to plot it?

How can I get data from For loops to use in ListStreamDensityPlot? I tried AppendTo, but it ...
661 views

### Plot 3D vector that is a function of one variable

I have a function, r[t], which is a piecewise function that generates a 3D vector. It looks like this: ...
104 views

### Implementing the Golden Section Rule

I am attempting to write a code which brackets the minimum of a unimodal function, using the Golden Section Method Below. I am have serious issues debugging my program though, any help will be ...
85 views

### Reduced interpolation order [closed]

I have a problem with Interpolation - the order is reduced to 1 no matter what, but I need a quadratic interpolation order. The ...
548 views

### How to simplify expressions containing derivatives

Is there a way to reverse the application of derivative rules in order to simplify expressions including derivatives? e.g. in Mathematica code: Want to go from ...
57 views

### Solve For X inside arc-cos function (with division) [closed]

Very basic but I've been stuck for more than 12 hours trying to solver this equation 20=360/(arccos(X/3200)*2) Can anyone solve X? and explain what exactly you ...
97 views

### How to integrate a table? [closed]

I have the following Table (dy/dx)={24,24.5,25,25.4} How do I proceed to interpolate the table and compute Integrate[Sqrt[1+(dy/dx)^2],{x,65,68}] ?
121 views

### plot data with small differences

I want to plot data with very small differences. I can't see the differences in my plot:
191 views

### How to pass arguments between functions

I have two Functions, f[] and g[]. f is passed some values ,say ...
28 views

### Recursion with an exception [duplicate]

I need to print the first 7 members of the sequence a[n] with its reccurence formula a[n+1]=7*a[n]+n, where a[1]=1 and the digit 7 dosnt occur.