# Differential Equations

- An equation involving derivatives of a function or functions. Solving ODE and PDE
 Meta Thread / Thread Starter Last Post Replies Views Views: 114,590 Announcement: Follow us on social media and spread the word about PF! Jan16-12 Please post any and all homework or other textbook-style problems in one of the Homework & Coursework Questions... Feb23-13 09:24 AM micromass 1 29,394 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 07:18 PM Luccas 95 135,835 Consider the following differential equations with initial conditions at time $t_0$ specified: \dot{x}_1 =... Oct20-13 09:14 PM Only a Mirage 0 402 Hello, Working through some reduction of order problems. I'm not sure about why the structure of a particular... Oct19-13 09:04 PM Simon Bridge 3 699 Good day. I was wondering if you could help me solve this first order linear partial differential equation: / = /... Oct18-13 11:25 AM berkeman 1 411 Something has been bothering me. I see a phrase like this: Plugging our two roots into the general form of the... Oct17-13 02:44 PM mesa 3 1,041 I ran into some formula: ^{a}_{0}∫J_{o}(kr) rdr= a/k J_{1}(ka) How can this be true? What property was used? Oct16-13 08:22 PM jasonRF 1 1,105 Helmholtz equation:##\nabla^2 u=-ku## is the same form of ##\nabla^2 u=f##. So is helmholtz equation a form of... Oct16-13 06:09 PM yungman 7 1,610 Hi, I'm trying to solve the flow profile inside an inhomogeneous porous material between two parallel moving plates... Oct16-13 05:07 PM Chestermiller 14 13,515 http://i.imgur.com/03izT8l.png Why is the math in the red box necessary? According to this definition, it isn't: ... Oct16-13 04:42 PM dextercioby 6 948 So, I'm trying to solve 2nd order linear differential equations (series solutions near a singular point). (lnx)y"... Oct16-13 10:58 AM Gridvvk 2 1,949 Hi all, If we have H'(r)=r+\tau(r)H(r) and \tau(r)=k+(H(r)/r)^a where Oct16-13 08:31 AM urbanist 2 582 I know nothing about DEs, so this may be a silly question. I'm given some time varying (x_t)_t and a constant r,... Oct13-13 06:18 PM economicsnerd 3 5,609 How can I determine the isotherms(curves of constant temperature) of given Temperature field like T = x^2 -y^2 + 8y.... Oct13-13 05:02 AM mfb 5 4,713 When solving a differential equation for Bessel Functions, how do you know when to use the 1st kind or Neumann... Oct13-13 04:30 AM SteamKing 1 614 I need to prove that the solution of this differential equation: dx/dt = -x3 + 2*x + sin3(2*pi*t) - 2*sin(2*pi*t) +... Oct12-13 12:31 PM pasmith 1 1,290 For possion equation $$u_{xx}+u_{yy}=f$$ I know the general five point scheme is in the form... Oct12-13 09:27 AM AlephZero 1 773 When the rod is infinite or semi-infinite, I was taught to use Fourier transform. But I don't know when should the... Oct12-13 06:00 AM HAMJOOP 2 1,128 Consider the harmonic oscillator equation (with m=1), x''+bx'+kx=0 where b≥0 and k>0. Identify the regions in the... Oct10-13 07:45 AM jfizzix 1 1,341 Hello... My main problem is to find the Green's function of this pde:... Oct10-13 04:29 AM andreasgeo 0 767 Hello, I'm now working on a charge limiting system. I tried modeling it an easy way to be studied. ... Oct9-13 05:37 PM carb 4 2,458 I'm finding for an example s.t. $$Δu=f , 0≤x≤1, 0≤y≤\frac{\pi}{2}$$ $$Δu=0, x>1 , 0≤y≤\frac{\pi}{2}$$ let take... Oct9-13 02:12 PM sigh1342 0 556 I was wondering if there is a generalization of the following (roughly stated) theorem to n-dimensional systems: ... Oct7-13 03:35 PM Only a Mirage 1 1,958 Hi all, I'd be very happy if you could help me solve a problem in my research. I need to prove the following: ... Oct5-13 06:34 PM pasmith 8 7,669 i got a book on differential equations that says a shortcut to solving the general differential equation... Oct5-13 06:28 PM fzero 1 670 Can you guys help with this question? i don't even know where to begin! *Cries* Thanks! I have a test tomorrow and... Oct5-13 12:03 PM epenguin 2 652 http://i.imgur.com/64ADMbk.png Are they both correct? Would the first or second solution be preferred? Oct4-13 08:27 AM HallsofIvy 7 4,306 I can't seem to model this properly. This isn't an assignment, I'm just curious how this will go, lol. So I have this... Oct4-13 07:52 AM Chestermiller 3 1,168 Not sure how this can be done. can anyone help? Oct3-13 04:15 AM SteamKing 3 1,223 The highlighted in yellow is a mistake, right? I might be going insane. Where does the PI go? Oct2-13 12:10 PM Turion 3 1,213 I have a function Z = f(P,T) and would like to calculate the partial differentials \left ( \frac{\partial... Oct2-13 10:50 AM Chestermiller 2 853 Hey I have a degree robotics and moved to theoretical physics so am still struggling to keep up with the mathematics.... Oct2-13 05:13 AM blade86 4 2,824 If we have \frac{1}{X(x)} \frac{d^2 X}{dx^2}=-κ^2, the literature is saying that the solution must be: e^(±iκx), but... Sep29-13 10:46 PM LCKurtz 6 1,784 I have a question about deriving the Bessel function of the second kind with integer order. I understand that the... Sep29-13 10:32 PM yungman 1 812 Hi all, I'm asking a question about the number of the boundary conditions in high-order PDE. Say, we are solving... Sep29-13 10:28 AM pasmith 1 1,284 Hello, In my Differential Equations class we are learning about modelling with first order differential equations.... Sep28-13 02:55 AM UltrafastPED 3 1,029 what are teh differential equations associated to Riemann Hypothesis in this article ?? ... Sep27-13 11:45 AM lostcauses10x 1 1,064 So we just started finding general solutions for homogenous&linear two-variabled PDEs by using separation of variables... Sep27-13 08:42 AM jasonRF 6 1,947 Should I just assume that any problems that involve integrating factor will always result in a perfect integral pair?... Sep26-13 02:40 PM GreenAce92 3 3,126 I'm new here, hope it is the right place to ask the question. The PDE question is ∂2u/∂x2+∂2u/∂y2=0 and... Sep24-13 09:11 PM hbl2012 2 2,370 Hello,I need somebody to help me in Mathematica programm I wrote code that works as a function which I can call when... Sep24-13 11:00 AM Bill Simpson 4 964 Hi, hope this is a right place to ask this question. I work in the soil physics field and this problem has taken lots... Sep24-13 07:30 AM Chestermiller 3 884