# Differential Equations

- An equation involving derivatives of a function or functions. Solving ODE and PDE
 Meta Thread / Thread Starter Last Post Replies Views Pinned: Intro. to Differential Equations ( 1 2 3 ... Last) My intent is to create a thread for people interested in Differential Equations. However, I will explicitly state that... Jul3-12 08:18 PM Luccas 95 117,165 Please post any and all homework or other textbook-style problems in one of the Homework & Coursework Questions... Feb23-13 10:24 AM micromass 1 24,534 HI guys. Haven't been here in a while... I have an algorithm attached that uses the levenberg marquardt non linear... Feb5-13 02:49 PM a.mlw.walker 0 779 Okay, kind of a silly question...but what do all of these stand for? ODE=Ordinary Differential Equations ( ;O I... Feb12-13 12:37 PM rodneychan 3 2,965 I would like to solve the non linear ODE \frac{d}{dx}f(x)=a f(x)+ b f^3 (x) with the boundary f(0)=0\quad... Feb9-13 07:28 AM galuoises 7 1,153 Hi everybody, I'm trying to find a solution for the 3D heat equation for pulsed surface heating of a semi-infinte... Feb28-13 01:44 PM rollingstein 19 2,262 got fourier series as a result of solving a PDE. how do i evaluate the converg. using average error in order to... Feb9-13 03:28 PM ChaseRLewis 2 784 I'm going to start my Master's in the Fall, and I'm attempting to teach myself Mathcad beforehand. I just installed it... Feb7-13 11:04 PM nissan4l0 0 495 Teaching myself PDE so I'm understanding Separation of variables it's pretty simple up to the point you need to... Feb8-13 01:39 AM Simon Bridge 1 508 It's been a little too long since I've has to do this. Can someone please remind me, how do you get from: ... Feb13-13 08:49 AM KenBakerMN 4 676 While studying the derivation of the normal modes of oscillation of a liquid sphere in the paper "Nonradial... Feb12-13 03:03 PM bigfooted 1 693 h''(t)=-\frac{1}{h(t)^2}, h(0) = h_0, h'(0)=v_0 The first step is to, I think, reduce this to a fist-order problem:... Feb12-13 06:59 PM Someone2841 0 466 https://skydrive.live.com/redir?resid=22F7BBABD7DEE83B!139&authkey=!AJNBw1fOd97ihTk Can anyone please help me work... Feb22-13 01:35 PM mfb 3 671 Hello everyone, can anyone help me with solving Laplace’s equation inside a semi-infinite strip. Is there specific... Feb21-13 04:29 PM pasmith 1 1,373 Hello everyone, I have a question that is bothering me a bit. I would be happy if you could give an idea or tell me... Feb22-13 09:50 AM HallsofIvy 1 650 I have seen a couple of solutions to this PDE - \frac{\partial x}{\partial u}=\frac{x}{\sqrt{1+y^{2}}} One is -... Feb27-13 05:03 AM AntSC 4 816 Hi, I am currently trying to plot and animate a wave function using the Schrodinger equation. I currently have... Feb23-13 06:17 PM Slide rule 0 637 Hi I was wondering what the Laplace transform of a squared differential is. With that I mean the Laplace of (y'... Feb25-13 08:36 PM the_wolfman 2 662 So, this is probably really easy, but it's been bugging me...is the following differential equation linear? ... Feb26-13 04:16 PM bigfooted 1 551 I'm trying to define Bessel's function by using the generating function, I know i need to go through a recursion... Feb27-13 05:21 PM mtomk 2 603 I have no idea how to start solving this ODE: y''(x)+(μ^{2}*c(x)+k^{2})y=0 Where c(x)=A+Btanh(ρx) with constant... Mar6-13 03:41 PM Mute 4 839 Is it possible for a surface to be obtained as the solution for a system of differential equations in a 3d phase... Mar4-13 03:52 AM marellasunny 2 787 Hello there, I am facing the second order ODE in the unknown function $$y(t)$$  \ddot{y} = a \dot{y} y - b... Mar1-13 05:46 AM muzialis 2 732 Consider the following PDE. A lot of this is from "Numerical Analysis of an Elliptic-Parabolic Partial Differential... Mar2-13 01:50 AM kai_sikorski 1 553 Hi, I am trying to solve a Poisson equation \nabla^2 \phi = f in \Omega, with Dirichlet boundary condition \phi = 0... Mar3-13 05:49 PM bhatiaharsh 3 659 (y^2)'' + (y^2)' + y^2 = 0 1) Is this DE linear? What if we substitute y^2 = h and solve for h y = sqrt(h) ... Mar3-13 05:39 PM pasmith 3 693 Are the equations listed below differential equations? If so, to understand them what level of calculus do I need?... Mar6-13 07:09 PM Jesse H. 5 801 I must say I'm utterly confused with the Annihilator method for solving Non-Homogeneous Constant Coefficient Second... Mar4-13 04:10 AM lurflurf 1 599 I have the following differential equation \frac{\partial}{\partial t}\left(\frac{a}{X}\right)+\frac{X}{b}\frac{... Mar10-13 12:26 PM Redbelly98 7 984 I have the following differential equation \frac{\partial b}{\partial... Mar5-13 02:50 AM JJacquelin 3 667 Note: I think I get too specific about the problem when what I am asking about a specific part of the whole problem. ... Mar5-13 12:54 AM Apophenia 0 495 I've got this problem, with relation to rates. is the concentration of one substance, is the concentration of... Mar8-13 11:08 PM Chestermiller 2 693 (r^2 \nabla^2 - 1) X(r,\theta,z) + 2 \frac{\partial}{\partial \theta} Y(r,\theta,z) = 0 (r^2 \nabla^2 - 1)... Mar7-13 08:41 PM DukeLuke 2 550 Hello I have the electrostatic equation like this ∇.(σ∇V)=∂ρ/∂t and if we write this in cylinderical coordinate it... Mar8-13 05:09 AM Mattw 0 463 is there an algebraic meaning to expressing the derivative of a function as (d^2)y/(dx)^2 in the liebniz way Mar10-13 08:48 PM WannabeNewton 5 731 I understand why this is a good method, but in one of the problems I am trying I yield 4 unknown parameters in a... Mar10-13 06:53 AM CAF123 0 536 Suppose we have discrete data {x⃗ } of a low-dimension nonlinear dynamical system,and I want to use the carleman... Mar10-13 12:06 PM xibeisiber 0 494 Hello, for the Poisson problem Δu = -1 on a 2D circular disk with u = 0 on the boundary, we have average(u) =... Mar10-13 10:12 PM Chestermiller 1 597 Hi, When solving for example Shallow Water Equations, the system itself is hyperbolic. Usually when dealing with... Mar14-13 05:39 PM bigfooted 1 660 I've separated the variables of this differential equation and end up with dx/((a-x)^(1/2)*(b-c(x-d)^3/2)). I've... Mar14-13 06:05 PM MegaFlyman 6 903 How do you differentiate kirchoffs law which seems to be I = (R+L(di/dt))/V(t) I need it to be a differential... Mar14-13 09:51 AM Needhelp2013 2 635 hello, guys Below is the equation I am concerned with: http://s019.radikal.ru/i608/1303/69/b494d7727c7a.png Is... Mar14-13 01:18 PM Ein Krieger 2 602