# 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 07:18 PM Luccas 95 121,411 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 25,903 Hello Did an exercise and a small simulation to expand f(x)=x, defined on 0 y=5e-2x+2x2+2x+1 1. What the Order of the ODE? It's 1st order 2 How do you check... Nov23-10 09:27 AM eskie 7 2,343 dx/dt= -x+y dy/dt= 2x x(0)=0 y(0)=1 I'm not familiar how to solve a system like this. Somebody plz help? ... Nov12-10 11:09 PM maverick280857 8 2,252 x' = y-2x y' = 2x-y Whenever you look for equilibrium points x'=0 and y'=0, y=2x for both cases. What is the... Dec2-10 05:52 AM epenguin 5 2,300 yIII+yII-yI-y = 0 I used the characteristic equation and got: r3+r2-r = 0 r (r2+r-1) = 0 Which means that... Nov12-10 06:29 AM HallsofIvy 1 13,401 I am considering a second order ODE of the form y''(x) + f(x) y(x) = 0, with boundary conditions that y(x) = 0 at... Nov12-10 10:16 AM mordechai9 0 2,226 Hello I'm trying to solve the following DGL with an integrating factor: x'=xg(y) y'=yh(x) which is... Nov13-10 10:44 AM heinerL 1 1,230 Hi, My differential equations professor wanted us to think about this problem: How would you go about modeling... Nov16-10 09:01 AM jambaugh 2 2,261 Hi there, I am a young mathematician and I have discovered that Dirichlet's boundary problem is ill posed... Anyone... Nov15-10 04:06 PM arildno 1 1,677 Hello, My course is a bit vague on this topic. 1 First of all it states: if the differential equation A(x)y''(x)... Nov18-10 08:03 AM HallsofIvy 1 2,038 Hi, Could someone please show me how to solve the following simple problem using the Runge-Kutta (RK4) integration... Nov18-10 08:54 AM HallsofIvy 3 1,923 Hello, S-function! in Simulink/Matlab does anyone solve ODE in S-function! in Simulink C++ blocks instead of... Nov18-10 12:05 PM mbolhi 0 2,045 The equation of motion of a rocket with mass depletion during ascent and subject to drag forces can be written as ... Nov22-10 01:57 PM Rruffpaw 7 2,654 I have an ellipse of a rl circuit and a rc circuit but now i am confused on how to obtain the phase angle. i know... Nov21-10 02:51 PM noname1 0 1,871 y''+9y=sin(3t) I need to solve the above using the method of undetermined coefficients. I have already found the... Nov23-10 11:11 AM phantomcow2 4 2,553 Hey everyone. I'm trying to refresh myself of solving linear ODEs. For simplicity's sake, I began by trying to solve... Nov23-10 02:24 AM arenaninja 2 1,231 Find the Particular Solution. Show the steps of derivation, beginning w/ the general solution.... Nov23-10 12:10 PM Matthew Rodman 1 1,005 x^2 y'' + x y' + n^2 y = 0 \; Is Euler equation and solution is y=x^m I understand the three cases with different... Nov24-10 09:30 AM HallsofIvy 4 1,508 I can not how define way to solve these equation x(l-x)y''+4y'+2y=o If any one can help Nov26-10 09:21 AM HallsofIvy 4 1,211 Hello, Thanks at first. If anyone can understand, then I would like to know how do I get to equation 4.15. Its a... Nov26-10 09:10 AM hgfalling 3 960 Hey Guys. Im trying to find an inverse laplace transform for fraction in the laplace domain but cant find it in any... Nov26-10 09:23 AM HallsofIvy 2 942 I was asked to seek for a harmonic function u(x,y) in the 2-dimention disk whoes boundry condition is... Nov26-10 03:26 AM JJacquelin 1 1,127 This appears on the bottom of p.279 of this book. The author begins with Green's second identity: \int_V \alpha... Nov28-10 02:21 AM kakarotyjn 6 1,323 why is a_{11} dy^2 - 2a_{12} dxdy + a_{22} dx^2 = 0 the characteristic equation of a_{11} \phi _x^2 + 2a_{12} \phi... Nov27-10 06:09 AM kakarotyjn 0 709 Zero input means input equals zero the input is to some differential equation D2x = Dx + x + Input the input =... Nov28-10 03:27 AM zhermes 3 1,412 Hey all! I'm trying to use the Runge-Kutta method on this differential equation but I am getting nowhere and it's... Nov30-10 02:31 PM EnumaElish 2 1,692 Suppose I wanted to know the surface integral of a recently whose points are (0,0,0),(0,0,2),(1,1,0),(1,1,2) The... Dec1-10 11:12 PM LCKurtz 1 934 The problem: You are given the problem of analyzing the dynamics of a line of cars moving on a one-lane highway. One... Dec1-10 05:13 AM jackmell 1 1,488 For the pde below $d^2G(x,y)/dxdy+(a(x,y)-1)*dG(x,y)/dx*dG(x,y)/dy=0$ how do I show the existence of G(x,y) given... Dec1-10 11:02 PM toptrial 0 874 Hello, Let us assume we have a differential equation ( \frac{d^2}{dx^2}+ \frac{2}{1+1/n}\Theta_n^{n-1} - \nu^2... Dec2-10 06:52 AM omyojj 0 985 I want to preface this by saying that these questions are not to find an exact answer, just to build intuition. If you... Dec4-10 09:53 AM farleyknight 0 1,787 Alright, so I have a general question on finding the general solution of the eq: ... Dec5-10 01:47 AM JJacquelin 1 1,613