Math Problem Statement

xy''+2y'=0

Solution

The given differential equation is:

xy+2y=0xy'' + 2y' = 0

Where:

  • yy'' represents the second derivative of yy with respect to xx,
  • yy' represents the first derivative of yy with respect to xx.

Step-by-Step Solution:

  1. Rearrange the equation:

    Divide the entire equation by xx (assuming x0x \neq 0) to simplify:

    y+2xy=0y'' + \frac{2}{x} y' = 0

  2. Solve the equation:

    This is a linear second-order homogeneous differential equation with variable coefficients. We can solve this using a method known as separation of variables.

    First, treat the equation as a first-order equation by defining v=yv = y', so that y=vy'' = v'. The equation becomes:

    v+2xv=0v' + \frac{2}{x} v = 0

    This is now a first-order linear equation in vv. We can solve it by using an integrating factor.

  3. Solve for vv:

    The integrating factor for the equation v+2xv=0v' + \frac{2}{x} v = 0 is μ(x)=e2xdx=x2\mu(x) = e^{\int \frac{2}{x} \, dx} = x^2.

    Multiply the entire equation by x2x^2:

    x2v+2xv=0x^2 v' + 2x v = 0 Which simplifies to:

    ddx(x2v)=0\frac{d}{dx}(x^2 v) = 0

    Integrating both sides with respect to xx, we get:

    x2v=Cx^2 v = C

    where CC is a constant of integration. Now, substitute v=yv = y':

    x2y=Cx^2 y' = C

    Solving for yy':

    y=Cx2y' = \frac{C}{x^2}

  4. Integrate to find y(x)y(x):

    Now, integrate yy' to find y(x)y(x):

    y(x)=Cx2dx=Cx+Dy(x) = \int \frac{C}{x^2} \, dx = -\frac{C}{x} + D

    where DD is another constant of integration.

General Solution:

Thus, the general solution to the differential equation is:

y(x)=Cx+Dy(x) = -\frac{C}{x} + D

where CC and DD are constants of integration.


Would you like a more detailed explanation of any part of this process?

Here are 5 related questions:

  1. How do we handle equations with variable coefficients?
  2. What is the method of integrating factors, and when is it used?
  3. How does the solution change if we have different coefficients in the equation?
  4. What happens when the equation involves non-homogeneous terms?
  5. Can you solve similar equations involving higher-order derivatives?

Tip: Always check whether the equation is homogeneous or non-homogeneous to choose the appropriate solution technique.

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Math Problem Analysis

Mathematical Concepts

Differential Equations
Second-order Linear Differential Equations
Separation of Variables
Integrating Factor

Formulas

y'' + (2/x)y' = 0
v' + (2/x)v = 0
Integrating factor: μ(x) = x^2
y(x) = -C/x + D

Theorems

Method of Separation of Variables
Solution of Linear Homogeneous Differential Equations with Variable Coefficients

Suitable Grade Level

College/University