# Tagged Questions

Questions on the use of numerical functions NIntegrate and NDSolve.

86 views

### How can I combine NIntegrate with NDSolve?

I have no idea how to calculate the problems. For example consider following differential equation (DE): ...
166 views

### How can I perform NIntegrate with NDSolve?

I'm a new user and I have no idea how to perform NIntegrate by using NDSolve. For example consider following differential equation (DE): ...
110 views

76 views

### Estimating error in NDSolve

I would like to give a theoretical estimation of local truncation error (and then for the global one) for a solution to a numerical initial value problem by NDSolve....
59 views

### NIntegrate some kind of highly oscillatory function

I have an analytical expression (exp) like this, See here. It is a kind of highly oscillatory function for (x1,x2,x3,x4). So,how to get the integral result by ...
45 views

### Order of evaluation for numeric functions

I'm trying to plot a 3D vector field to illustrate an electric field of a uniformly charged disk, and I used Manipulate to change the radius R of the disk to see ...
74 views

### NIntegrate problem with limits in triple integral [closed]

So I am trying to solve a triple integral in mathematica, but I am getting errors regarding my limits of integration. This is my code: ...
453 views

### Solving an equation involving an integral

How do I get the following into Mathematica, solving for $a$: $$0.7 = 1 - \frac{2}{a} \times \left[ \frac{1}{a} \int_0^a \frac{x}{\exp(x)-1}\mathrm dx + \frac{a}{6} - 1\right]$$
49 views

### Time needed to solve NIntegrate is much longer than what I was expecting

I'm trying to do the following list: tablevdip = ParallelTable[{x, y, Vdip[x, y, 6]}, {x, -1, 1, .5}, {y, -1, 1, .5}];] with ...
72 views

### Avoid Evaluation of Function at NDSolve

I have a huge "black-box" f function, which I want to integrate. Let's define it: f[x_,y_,a_]:=a*Exp[-(a*10000)(x^3+y^3)] as ...
107 views

### Integrating high oscillatory function - triple integral - error message

I am working in a triple integral, but the second integral (qQ) and the first too ( aA ) is a oscillatory funcion. The third integral ( os11 ) is like a gaussian, and is easy to integrate. i am ...
114 views

### Solving nonlinear 3rd order ODE over range from zero to infinity

Here are the code that I had tried but there is an error ...
175 views

### Plotting singular integral

I need to plot the following singular double integration $u(x,t)$ for $t=0, t=0.2, t=0.4, t=1$ and $t=2$ in one figure as a line. That is, I need $u$-coordinate vertically and $x$-coordinate ...
80 views

### Nested NIntegrate with variables in limits

How do I solve nummerically something like this and plot a function for it? $f(x)=\int \exp[\int ^{x+y} _{x-y} \exp(z) dz]dy$ This example has analytical solution, however I would like to know how ...
77 views

### WorkingPrecision and NDSolve Method Plugin Framework

I'm studying some new numerical integration algorithms using NDSolve Method Framework to specify them. When I try to set ...
62 views

### WhenEvent behavior changed from v9 to v10 - how to fix the code?

A couple of years ago I asked a question about solving n-body systems with NDSolve and detecting collisions with WhenEvent. I ...
97 views

### Function where variable is integration bound

Lets say I have a function of the form: $f(T) = T^4 \int_0^{1/T} \frac{x^3 dx}{e^x-1}$ This is an example of the situation I am describing not a unique problem. I want to define it as a numerical ...
198 views

### Certain integral over torus

Let $F(t_1,s_1,t_2,s_2)=$ $$\big((2+\cos t_1)\cos s_1 - (2+\cos t_2)\cos s_2\big)^2 + \big((2+\cos t_1)\sin s_1-(2+\cos t_2)\sin s_2\big)^2 + (\sin t_1 -\sin t_2 )^2.$$ I am interested in computing ...
188 views

### How do I plot this 3-D, double integral?

I have the following function: I need to plot a 3-D with coordinates f (p, q), p and q. I mean, I enter values for p and q, so that the integral of f (p, q) must be a number. This number must be ...
319 views

144 views

### Trapezoid Integration over a list of pairs [duplicate]

I have two very connected questions: Is there really no built-in function to integrate a list of pairs without converting to a function? Something like: ...
182 views

### Solving non-linear differential equation

For my research project I need to solve the following integral ...
103 views

### Problem with NIntegrate and FindFit [closed]

I fit the experimental curve with the model using the following equation, ...
50 views

### Problem with curve fit using integral [closed]

I need fitting a Langevin function on a experimental data, but one parameter must be firstly optimized by using a Lognormal distribution. The complete expression could be written as: The integrate ...
237 views

### How to locate the position of a periodic orbit

These are the equations of the dynamical system ...
120 views

### Can't NIntegrate my NDSolve results

I want to NIntegrate my NDSolve result. I don't have a exact function form because it is coming from the ...
60 views

### WhenEvent stops working after first instance

I'm modelling a very simple physical situation is which an object is rested on two moving fingers. Sometimes the object moves with one finger while sliding over the other, while at other critical ...