# Differential Equations

- An equation involving derivatives of a function or functions. Solving ODE and PDE
 Meta Thread / Thread Starter Last Post Replies Views Views: 124,182 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 29,623 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 95 136,750 I used the linear equation method to solve a D.E. and got y=3/4 at the end. I'm asked to find the interval of... Jan28-13 12:41 AM Mark44 5 739 I get confused when it is 'ok' to use the natural logarithm when integrating a function. As soon as I see a... May25-10 03:00 AM Shaybay92 2 2,741 On a 2 dimensional Riemannian manifold when is a vector field with isolated singularities the Lie bracket of two... Sep13-11 01:58 PM lavinia 0 970 Greetings, I faced with a problem that states - Find slope of the tangent line to 〖 x〗^4 – xy^2+ 4xy^2 = 20,at... Oct23-10 11:37 PM ngm01 2 1,156 Apparently it is a well-known fact that if G(x)=(G_{ij}(x_1,\ldots,x_n)) is a smooth nxn matrix-valued function such... Mar20-14 03:04 PM quasar987 0 461 I'm doing a course in PDEs, where the lecturer hasn't really explain when all these methods for solving PDEs are... Nov4-09 11:52 PM jasonRF 2 1,144 I have some confusion about when separation variables can be applied to a PDE. Can it be applied on any PDE that can... Apr6-10 10:15 PM hosun 1 714 I have to find a non-trivial, linear combination of the following functions that vanishes identically. In other... Nov4-10 07:45 PM warfreak131 6 3,817 Just a small list, mark up any others I have neglected... :cool: edit: already see, I should've put in PDEs with... Mar27-06 10:46 PM Clausius2 2 1,535 I have an equation like this, \frac{dZ}{zD\beta} = \frac{d}{d\beta}\ln Z, is it from... May6-13 10:36 AM pattisahusiwa 3 611 I recently came across the NS millennium problem and I read that uniqueness for the NS equations is unknown. I have... Nov4-11 06:13 PM myshadow 2 1,729 I show a graph where errors in perceived angles of stimuli increase with the underestimation of lengths of stimuli. I... Feb20-12 12:26 PM PatternSeeker 4 1,322 I'm learning fluid mechanics, and I am confused about the following differential operators. What's the difference... Apr23-10 03:06 AM Thaakisfox 1 894 As the thread title says: What's the difference between initial conditions and boundary conditions? Thanks in... Mar31-09 06:43 PM HallsofIvy 9 19,777 That's my question,let's suppose i define the functions: G(x,s)=exp(x-s)^{2} and R(x,s)=(e^{st}-1)^{-1} My... Oct11-06 11:05 AM Karlisbad 0 1,555 Hi there, My equation to solve is (xy+(x^2))dx + (-1)dy=0 For method of exact solutions, the partials are not... Oct29-11 08:12 AM lurflurf 1 1,418 I've been working through an equation for awhile and finally reduced it to a differential equation I have to solve,... Aug24-05 11:56 PM Lyuokdea 9 1,535 Hi all! In this differentail equation, what particular should I try? Is it correct to try " exp(-2x)"? May15-05 07:40 PM saltydog 15 2,094 Just learned that diffusion equation loses information as time goes on,i.e. given the initial condition at t=0, we... Feb24-11 05:48 AM kof9595995 0 583 I'm trying to follow a proof for the solution of the diffusion equation in 0 < x < l with inhomogeneous boundary... Oct3-10 03:30 PM jackmell 1 1,089 I am trying to solve a real-world problem, and I have modeled it with the following equation: \frac{dS}{dt}-3\left... Nov5-11 06:15 PM yus310 4 1,748 Does it have an easy classification (elliptic, hyperbolic, parabolic, for example)? Or does the fact that it has an... Oct19-12 04:24 PM Mute 1 1,104 Hi all. I am reading things about wave theory. I am rather confused about the term "weakly nonlinear". Say for the... Jun27-10 07:02 AM HallsofIvy 3 3,550 Hello everybody, What is this equation called? I'm from non-English speaking country and I need to look up materials... Jun21-13 12:29 PM Goethe10 6 768 When I was scanning the materials of Bessel function, I found that when the variable is: xe^{\frac{3\pi}{4}i} ... Feb27-12 07:29 PM Chuck88 8 1,919 I'm trying to analyze the following Ito stochastic differential equation: $$dX_t = \|X_t\|dW_t$$ where X_t,... Apr18-14 06:57 PM Only a Mirage 2 318 Hi Max, Thanks very much, but now I am puzzled solving this problem: F'''+FF''/2=0 F'(-infinite)=1... May29-04 05:19 PM Clausius2 4 1,888 I am seeking an EXACT solution of this sistem of ODE's, in which g(x) and f(x) are the unknown functions: ... May10-04 03:14 PM Clausius2 26 3,900 how can we solve this differential equation? (ax+y)∂f/∂x + (ay+x)∂f/∂y =0 with this condition: if a=0... May9-14 02:29 AM JJacquelin 2 333 I have flipped through the first few pages of Evan's PDE book lately, and I am considering taking a graduate PDE... Aug24-09 04:57 PM ephedyn 6 1,883 Hi everyone, I'm currently learning about finite-element methods and I'm having trouble understanding the motivation... Mar14-12 02:38 PM bigfooted 11 2,260 Everybody knows one dimensional wave equation \frac{\partial^2u}{\partial t^2} = c^2 \frac{\partial^2u}{\partial x^2}... Apr27-10 09:06 AM Hootenanny 1 5,889 \nabla^2 V = \nabla \cdot \nabla V. Let me first break this down in English from my understanding: \nabla V is... Nov2-10 06:36 AM MasterX 3 4,439 The definitions of a harmonic function u are: It has continuous 1st and 2nd derivatives and it satisfies \nabla^2 u =... Aug3-10 08:18 PM Mark44 10 1,970 F(s) = \frac{1}{K^s} where K is a positive real. Jun13-10 05:10 PM Count Iblis 3 1,663 im having problem integrating the equation dydx=y^2/x^2 and also dydx=3*y^2/x Apr9-10 07:14 AM StalkerM 2 2,244 What is the difference between simple fixed pole and simple movable pole? Differential eqs. z(dw/dz)+w=0,... Apr20-11 08:03 AM JJacquelin 1 661 For example, if y=x^2, then the derivative of y is 2x. We write the derivative as either f'(x)=2x or dy/dx=2x. ... Dec27-12 12:05 PM HassanEE 5 4,058 On Wolfram Alpha it will offend give you a contour plot, and it has similarities to a bifurcation plot with respect to... May13-14 12:34 AM alan2 2 422 How would you define what a coefficient is in the context of differential equations? How do they influence the graph... Jul1-12 03:45 AM chiro 1 734