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1
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1answer
49 views

Strange constants in a PDE solution by DSolve

I'm solving the following PDE: DSolve[F''[ξ] + (Ω^2 - M^2 Exp[2 α ξ]) F[ξ] == 0, F[ξ], ξ] And Mathematica gives a general solution in terms of modified Bessel ...
1
vote
0answers
37 views

NDSolve: Equation with interpolating function [closed]

I have a question regarding DSolve and NDSolve functions in Mathematica 10. For instance, I'd like to solve an ODE: ...
0
votes
1answer
70 views

Parametric Plotting

I am trying to make a parametric plot of the x and y displacements of a vibration problem. When trying to plot the parametric curve won't show up.
0
votes
0answers
43 views

when DSolve fails

I am doing this mathematical problem $c*G_{vv}+ d*G_{u} + e*G_{v} +f*G=0$, where $c, d, e$ and $f$- are constant coefficients. I already know that this is second order PDE and we classify it by ...
4
votes
1answer
172 views

How to solve this Integral equation

D[x[t] - x[t - 1]/(2 E), {t, 3}] + Integrate[E^(-δ)*x[t - δ]/5^t, {δ, 2, 2.5}] == 0 I found solve this problem is hard with Mathematica. I also find a article ...
0
votes
1answer
34 views

DSolve for first order nonlinear equation is solution numerical or analytical?

Hi I'm new to mathematica so I may have a somewhat trivial question. my code below solves and plots the results of a first order nonlinear ODE. The solutions mathematica gives me contains & and #1 ...
1
vote
0answers
85 views

Why is my output equal to my input?

I tried to solve a system of differential equations with the code below: ...
0
votes
2answers
66 views

DSolve bvlim error due to Boundary condition at infinity

I am solving an Ode using Mathematica that has boundary condition at infinity which is why Mathematica is showing error message. Please help to tackle this problem. ...
0
votes
0answers
36 views

DSolve echoes input

I'm attempting to solve a set of coupled, non-linear ordinary differential equations using DSolve, but Mathematica simply echoes the code that I put in: ...
1
vote
1answer
65 views

Fit to inverse function

I am trying to fit my data to an inverse function from solving a DGL: ...
0
votes
1answer
37 views

Why does DSolve fail here?

I have the following differential equation: a*L'[t] == 40000*L[t]^(-3/2) - 1.4 - extf I want to fit the solution to data in order to acquire a. I tried DSolve ...
0
votes
1answer
34 views

Problem with DSolve [closed]

I am trying to use DSolve: DSolve[{y'[x] == x/y, y'[8] == 2}, y[x], x] But I get an error message: DSolve::dvnoarg: The ...
5
votes
0answers
80 views

Second order differential equation with boundary conditions solving repeatedly

I want to solve a second order differential equation in the interval[-1:1], which does not have a analytic solution, \begin{eqnarray} y''(x) &=& k \phi^2(x)y(x) \\ \phi(x) &=& ...
0
votes
0answers
54 views

How to solve system of non linear Differential Equations with 1 independent variable and 3 dependent variables?

I have been trying to solve this system of differential equations using mathematica. $$F(t) B''(t)+B'(t) F'(t)+B(t) F''(t)=0,\\ F(t) A''(t)+A'(t) F'(t)+A(t) F''(t)=0, \\ B(t) A'(t)+A(t) B'(t)=0$$ Here ...
0
votes
1answer
53 views

How to evaluate a “pure function”? [closed]

I need to evaluate the result of DSolve, e.g. {{y -> Function[{x}, x^2 - x^3]}} at some specific point. I tried y[1] and y /. x -> 1. Hope someone knows how to do it
0
votes
0answers
36 views

Boundary condition is not specified on a single edge of the boundary of the computational domain

When I want to solve this PDE I get this error "NDSolve::bcedge: "Boundary condition u[0,0.05]==0 is not specified on a single edge of the boundary of the computational domain"" ...
7
votes
2answers
179 views

Solving with DSolve recursively

I need to find $f(x,n)$ in the interval [0,1] defined by recursion, \begin{equation} \frac{d f(x,n+1)}{dx} = f(x,n) \end{equation} with boundary conditions $f(0,n+1) = 1$ and $f(x,0)=1+ x $ Using ...
4
votes
2answers
56 views

DSolve results not what expected

I have the following formula: s'[t] == 230.94 Tan[0.914743 - 0.138564 t] When I solve this by hand I get: ...
0
votes
1answer
62 views

DSolve not returning “trivial” solutions [duplicate]

When I enter this DSolve[y'[x]^2 + y[x]^2 == 1, y[x], x] the answer I get is ...
0
votes
2answers
72 views

Solve simple differential equation - Error?

I get the error "The function Te appears with no arguments." when running this code. I'm not sure why. Is it because of the $Abs[\Gamma]$ ? ...
0
votes
1answer
124 views

Problem with NDSolve [closed]

I'm solving a PDE that is partially elliptic. So I need to solve the equation iteratively. My problem is at the end of the code. I'm doing interactions manually in order to evaluate the code. At the ...
6
votes
2answers
182 views

Problem when defining function through NIntegrate and NDSolve and Interpolation - Bug?

More than a single question, I have some doubts about the output of certain functions when defined through the result of other calculations. I am an active user of Mathematica, but maybe I haven't ...
-1
votes
1answer
81 views

How to get solution from DSolve

How to get the solution from DSolve in such way that there is no need to copy the result. When for example solving: ...