# Differential Equations

- An equation involving derivatives of a function or functions. Solving ODE and PDE
 Meta Thread / Thread Starter Last Post Replies Views Views: 828 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 30,075 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 95 138,276 What is the vector space under consideration when we say that a linear differential equation is of the form Dy=f ... T 12:21 PM pasmith 11 301 Is it possible to solve a differential equation of the following form? $$\partial_x^2y + \delta(x) \partial_x y +... T 03:55 AM Simon Bridge 2 1,998 For the following problem \frac{dw}{d\theta}=\theta w^{2}sin(\theta^{2}), w(0)=1 I am not able to obtain the... Aug21-14 03:12 PM rjr 4 1,258 Hi friends i am trying to solve heat equation for a single time domain,with Finite Difference Method. I wrote a... Aug20-14 02:52 PM Strum 2 176 Suppose all second partial derivatives of F = F (x, y) are continuous and F_{xx} + F_{yy} = 0 on an open rectangle R. ... Aug19-14 10:47 AM Medicol 3 179 Greetings all ! This is my first post on the forum, so please kindly let me know if I am not asking a proper... Aug18-14 03:12 PM atto 4 237 I want to solve the following differential equation using matlab and thus want to plot between x & y.... Aug17-14 04:27 AM da_nang 1 114 hi pf! ok, so my math text for PDE's states the following theorem:$$f(x) = \sum_n a_n \phi_n (x)$$for "nice... Aug14-14 11:25 PM Shyan 8 298 Hi, while solving differential equations problems we have to sometimes use absolute value while taking an integral of... Aug13-14 11:30 AM HallsofIvy 3 184 Hi guys , I'm currently reading a book and I faced this with DEs: In the 5 attached images you'll find the textbook... Aug8-14 11:50 PM Simon Bridge 1 312 Hi everyone, i am trying to solve and program a non linear differential equation in matlab where thermal conductivity... Aug8-14 11:04 PM Chestermiller 7 209 http://www.math.uiuc.edu/documenta/vol-ismp/40_lemarechal-claude.pdf I don't understand why we use theta for... Aug8-14 07:32 AM HallsofIvy 1 192 Here's the problem: Find the general solution of x*dy/dx+2y=10x^2. How do I find the answer for this problem on... Aug7-14 07:50 AM Sunfire 2 193 This is a bit counterintuitive to me that the gradient vector is always normal to the level curve and the level... Aug6-14 07:12 AM HallsofIvy 2 190 Hi all, first of all I apologise if my question is not supposed to be in this thread. I am a fledgling mathematician,... Aug5-14 11:22 PM Greg Bernhardt 1 242 Can anybody give me some links for plotting bifurcations online? Aug5-14 11:22 PM Greg Bernhardt 1 352 Suppose we have some partial differential equation for a scalar ##f##$$Df = \rho$$taking values in... Aug5-14 11:22 PM Greg Bernhardt 1 747 does negative divergence of gradient tempearature gives to lalace equation...? -div(∇T) = Aug5-14 07:32 PM SteamKing 1 163 I want to be able to map the position of a planet given initial position, velocity, and acceleration. I know the... Jul30-14 08:21 AM Juan Carlos 2 2,223 Hi!, I'm working on a personal project: Solve the heat equation with the semi discretization method, using my own... Jul30-14 08:08 AM Juan Carlos 2 239 Hey there, I have modeled a propagating wave in a 1D dispersive media, in which square and cubic nonlinear terms... Jul30-14 01:14 AM Strum 2 1,963 How to understand Uniqueness and existence theorem for first order and second order ODE's intuitively? Jul28-14 02:51 PM homeomorphic 3 466 Hi. First off, sorry for the not so descriptive title. If one of you finds a better tilte I will edit it. We have... Jul28-14 03:27 AM Strum 1 785 Hello Everyone. I have a question. Suppose I have a differential equation for which I want to find the values at... Jul26-14 12:39 AM crossfire234 1 785 I'm currently reading Tolstov's "Fourier Series" and in page 58 he talks about a criterion for the convergence of a... Jul25-14 02:49 PM jbunniii 2 702 When deriving the Runge-Kutta Method to solve y'=f(x) we need to use Taylor expansion. Hence we need to differentiate... Jul23-14 01:30 AM matematikawan 4 921 My textbook says that: "A differential equation contains both the function and the derivative of the function" ... Jul22-14 04:31 PM johann1301 3 856 I want to show, in a talk, how to build the Predator-Prey (Lotka Volterra) model. It starts off with the "Population... Jul22-14 07:09 AM dkotschessaa 2 742 According to the confluent hypergeometric equation \frac{d^2}{d x^2} y + \left(c - x \right) \frac{d}{d x} y - a y =... Jul20-14 03:44 PM Domdamo 3 2,146 Hi, I'm trying to find the first integral of motion for this set of PDE. I'm not really that familiar with this... Jul17-14 11:44 AM Alicelewis11 2 3,465 Hi - wondering if you can help me find a solution of: \nabla^{2}u-\frac{u}{\lambda^{2}}=a\delta(r) for spherical... Jul17-14 09:17 AM jasonRF 3 2,569 Consider the following linear functional operator:$$Q_w = \lim_{h\rightarrow w} \lbrace \frac{f(x + h) - f(x)}{h}... Jul16-14 06:17 PM da_nang 1 1,477 Does anyone know how to prove this identity? I don't quote understand why the associated Legendre function is allowed... Jul16-14 05:19 PM HasuChObe 2 1,287 Hi, I am having a problem implementing 4th Order Runge Kutta (RK4) to solve a non linear ODE. dy/dt = B(t) -... Jul16-14 03:04 PM AlephZero 2 1,371 I'm doing a practice problem I found online, and I get a solution, but I think it should have a sine term in it. I... Jul14-14 06:21 AM pasmith 1 1,742 As it can be read here, http://en.wikipedia.org/wiki/Laplace_transform#Relation_to_power_series the Laplace transform... Jul12-14 08:23 AM HallsofIvy 2 1,624 For a regular LR circuit (L and R in series) and with a AC voltage: http://i.imgur.com/R8yRjNY.jpg I tried to... Jul11-14 05:18 AM Waxterzz 2 1,924 Hi, Are there any numerical techniques I can use to solve differential equations with periodic boundary conditions? I... Jul10-14 04:44 PM SarthakC 8 2,074 This is about attempting to solve ##\left( y'\right)^2 = y^2 - 1 ##. \int\frac{dy}{\sqrt{y^2 -1}} = \pm \int dx ... Jul9-14 05:47 AM pasmith 2 1,547 f(z) = sq. rt of z-1 / z+1 --- both numerator and denominator are inside the radical. I can write it as (z-1)^1/2... Jul7-14 07:33 PM HallsofIvy 2 1,935