Homogeneous Definition and 382 Threads

  1. B

    Help with linear homogeneous recurrence relations

    Homework Statement Here's my problem - Give the order of linear homogeneous recurrence relations with constant coefficients for: An = 2na(n-1) The Attempt at a Solution I have no idea on how to start this problem - Any help would be greatly appreciated.
  2. S

    Nonlinear Homogeneous Differential Equation Solution

    Homework Statement I'm told that this is homogenous (x^2-xy)y'+y^2 = 0 2. The attempt at a solution This is going to be very painful for me to type out... (x^2-xy)\frac{dy}{dx} = -y^2 \frac{dy}{dx} = \frac{-y^2}{(x^2-xy)} \frac{dy}{dx} = \frac{-y^2}{(x^2-xy)}...
  3. S

    Understanding Homogeneous Differential Equation Simplification

    This is a basic simplification, but I'm going to post this here because it becomes homogeneous, and I know v = \frac{y}{x} but I don't see this simplification, I don't understand how it gets from this... \frac{dy}{dx} = \frac{y-x}{y+x} To THIS: = \frac{v-1}{v+1} (I'm just only showing...
  4. D

    Why Can an Equation Be Homogeneous but Incorrect?

    im posed with the question why an equation may be homogeneous with respect to its units but still be incorrect? i can't think of way to explain this can anyone help me out? Thanx
  5. P

    Difference between spatially homogeneous and isotropic?

    What are their differences? Spatially homogeneous is when there is uniform composition of space Spatially isotropic is when you look anywhere, they look the same Is it the case that one is visit anywhere, it is the same and the other is look anywhere they look the same? They seem...
  6. T

    Solving Homogeneous Problem: Initial Value & Substitution

    Hi all, I have been given this question: Find the initial value problem of the homogeneous equation: (x^2 - y^2) y' = xy \ , \ y(1) = 1 Now I know, from my lessons, I have to get it in the form of: \frac{dy}{dx} = f(\frac{y}{x}) I have managed to get close but nothing is...
  7. D

    Solve homogeneous first order PDE's

    u_x+u_y+u=e^{x+2y}, y(x,0)=0 I have no idea how to do this. We were only taught how to solve homogeneous first order PDE's.
  8. D

    ODE particular solution of the homogeneous equation

    y''(t)+A^2y(t)=f(t), t>0, y(0)=B, y'(0)=C, A, B, C\in\mathbb{R} e^{iAt} is a particular solution of the homogeneous equation. I can multiply it by some arbitrary function and find another solution of the homogeneous case, but when I try with the f(t) on the RHS, I can't do it. Anyone help?
  9. D

    Showing Integration Factor of Homogeneous Equation of Degree n

    Hey... So the question is as stated: Show that \frac{1} {M_x + N_y} , where M_x+N_y is not identically zero, is an integrating factor of the homogeneous equation M(x, y)dx+N(x, y)dy=0 of degree n. So I am not too sure where to go with this. I suppose what it's saying is, that I'm...
  10. K

    Higher Order Homogeneous ODE (IVP)

    Higher Order Homogeneous ODE (IVP) [Solved] I am having problems with this IVP: y'''' + y' = 0 y(0) = 5 y'(0) = 2 y''(0) = 4 What I have done so far is: \lambda^3 + \lambda = 0 \lambda(\lambda^2 + 1) = 0 So one roots is \lambda = 0 (though.. can there be a root that...
  11. Z

    Homogeneous Differential Equation

    Solve the initial value problem y''' - 5y'' + 100y' - 500y = 0; y(0) = 0, y'(0) = 10, y''(0) = 250 given that y_1(x) = e^5x is one particular solution of the differential equation. r^3 - 5r^2 + 100r - 500 = 0 r = +/- 10i or 5 complementary solution y_c = e^5x(c1cos10x + c2sin10x) general...
  12. A

    Differentiating Homogeneous Functions: A & B

    Well actuallly 2 thms. They have to do with homogeneous functions. f(tx1,...,txn) = t^k * f(x1,...,xn). Now how do you show A) d/dx1 f(tx1,...,txn) = t^k-1 * d/dx1 f(x1,...,xn) and B) kt^(k-1)*f(x1,...,xn) = x1*d/dx1 f(tx1,...,xn) + xn*d/dxn f(x1,...,xn) A) In the book They say that...
  13. M

    Question on homogeneous linear systems

    I have a homework question that I don't really understand what they are asking. The book I am using is terrible so I was hoping someone could shed some light. Question: Give a geometric explanation of why a homogeneous linear system consisting of two equations in three unknowns must...
  14. A

    Solving a Homogeneous Linear Equation for x>0

    Can someone give suggestions for this question? Find a basis of solutions for the following second-order homogeneous linear equation for positive x: x^2y``-xy`+y=0
  15. T

    Homogeneous system of linear equation:

    I am having trouble finding the solution to the homogeneous system of linear equations: 2x-2y+z=0 -2x+y+z=0
  16. F

    Solving a Homogeneous ODE: Step-by-Step Guide

    Hi, I'm having trouble with this ODE: [FONT=Times New Roman]y' + 4xy - y^2 = 4x^2 - 7 [FONT=Times New Roman]=> y' = 4x^2 - 4xy + y^2 - 7 = (2x - y)^2 - 7 => x(dv/dx) + v = (2x-vx)^2 - 7 = x^2(2-v)^2 - 7 I assume this ODE is of the homogeneous type, so...
  17. S

    Why must every homogeneous system of planes have at least 1 intersection point

    Well, I'm doing homework (again). I was introduced to homogeneous systems of planes and then asked why there must be at least 1 intersection point. The book gives very little (one sentence) on homogeneous systems so I tried to search around online. My guess is that since all of the...
  18. G

    Homogeneous and particular solution

    hi, I have this ODE and I need to obtain the general and the particular solution, this is the ODE Vz''+1/r*Vz'= k where k is a constant thanks
  19. L

    Understanding S^2 as the Quotient of SO(3) and SO(2)

    I've seen S^2 written as the quotient SO(3)/SO(2). Can someone run me through how to show this, or point to somewhere that does, as I've only seen it stated?
  20. N

    How to Determine a Differential Equation from a Given Solution?

    Q. Determine a homogeneous linear differential equation with constant coefficients having having the following solution: y = C1sin3x + C2cos3x My idea is to differntiate both sides with respect to x and come up with an equation in dy/dx what else? can be done... Is my idea correct.
  21. A

    Second-Order Homogeneous Linear Equation

    I have this intial value problem: y''-4y'-5y=0, y(1)=0, y'(1)=2. My AUX equation is r^2-4r-5=0. I factor and get r=5, r=-1 and my equation becomes y(x)=C1e^(5x)+C2e^(-1x) (C1 and C2 are constants). I took the derivative of y(x) and then tried to use my initial value's to solve for C1 and C2. I...
  22. C

    How do I prove the homogeneity of a function of degree n?

    Hi " A function f is called homogeneous of degree n if it satisfies the equation f(tx,ty,tz)=t^n*f(x,y,z) for all t, where n is a positive integer and f has continuous second order partial derivatives". I don't have equation editor so let curly d=D I need help to show that...
  23. N

    Homogeneous Differential Equations

    Hi, I need some help in finding whether this differential equation is homogeneous or not. 3 (d^2 y / dx^2) + x (dy/dx)^2 = y^2 I know that for example, x^2 dx + xy dy = 0 is homogeneous. But how can I deal with the equation that has (d^2 y / dx^2) and (dy/dx)^2 ? Thanks
  24. G

    Show that the equation is homogeneous

    Show that the equation is homogeneous with respect to units: I = nAQv I can't prove it, please help
  25. K

    How Does Substitution Work in Solving Homogeneous Differential Equations?

    The book only has one example of this and it's really confusing me. (x^2+y^2)dx+(x^2-xy)dy=0 I can see that it's homogeneous of degree 2 They then let y = ux From there they state that dy = udx+xdu (I'm not sure where this is coming from, but can just accept it on faith if I have to)...
  26. cepheid

    General Solutions of 2nd Order Linear Homogeneous Ordinary D.E.s

    A theorem in my textbook is confusing me: For the functions p(t) \ \ \text{and} \ \ q(t) continuous on an open inteval I defined by \alpha < t < \beta : We have differential equation L[y] = 0 where L = (\frac{d^2}{dt^2} + p\frac{d}{dt} + q) The theorem attempts to prove...
  27. A

    What is the solution for the homogeneous equation (x^2 + y^2)dx + (2xy)dy = 0?

    (x^2 + y^2)dx + (2xy)dy = 0 I get y = sqrt((kx^5 + x^2)/3) Where k = c2 cubed, and c2 = ln(c) so k = 3ln(c) But, the answer the teacher gave is (x^2)(y^3) - x - ln(y) = c I can't come up with anything remotely close. I know this isn't in a pretty LaTeX form, but I am new and haven't...
  28. cepheid

    Is Homogeneous Always Separable in First Order Differential Equations?

    Hi, Please bear with me, I've only had the first sort of "pseudo-lecture" in ordinary d.e.'s this past week, and I was doing some reading ahead. It occurred to me that if linear first-order differential equations are those that can be written in the general form: \frac{dy}{dx} + P(x)y =...
  29. L

    Homogeneous linear system question

    Hi, i have a question. Hope you guys can help~ Ques: Give a geometric explanation of why a homogeneous linear system consisting of 2 equations in 3 unknowns must have inifinitely many solutions. What are the possible numbers of solutions for a nonhomogeneous 2 x 3 linear system? Give a...
  30. Antonio Lao

    Is Cosmos Homogeneous, Isotropic ?

    Is Cosmos Homogeneous, Isotropic ? Is the universe really homogeneous and isotropic? The answer is hidden within the structure of spacetime.
  31. N

    Homogeneous Equation (easier question)

    Can someone explain what the homogeneous equation is :redface: and how do you find the 'null vectors' and hence the general solution. Eg. AX = [6] [8] [4] A = [1 2 4] [3 1 2] [0 2 4] X = [2] [0] [1] Find the null vectors of A and general solution.
  32. S

    Homogeneous points & coordinates

    Hello all! I'm taking a look at Meserve's "Fundamental Concepts of Geometry" for an introduction to the world of geometry. Section 1-7, A geometry of number triples completely confunded me. It introduced homogeneous points, and in my opinion it either a) did a horrible job, or b) did a horrible...
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