General solution for homogeneous equation

In summary, the conversation is about finding the general solution for a given homogeneous equation. The equation is manipulated using substitution and an integrating factor is used. However, the final solution is not clear and further help is needed.
  • #1
magnifik
360
0
i am having trouble finding the general solution for the given homogeneous equation:

x2yy' = (2y2 - x2)
which i made into
x2dy = (2y2 - x2) dx

i turned it into the following:
(2y2 - x2) dx - x2 dy = 0
then i used substitution of y = xv and got
(2(xv)2 - x2 - x2v) dx - x3 dv = 0
then i turned this into the following ... i think this may be the part i did wrong
(2v2 - 1 - v) dx - x dv = 0
then the integrating factor was
1/x(2v2 - 1 - v)
so...
dx/x - dv/(2v2 - 1 - v) = 0
i am stuck here. i know the first part is ln x, but I'm not sure if the second part is [ln (2v2 - 1 - v)]/(4v - 1)...if this part is right then i am stuck again here. i don't know how to get to the final solution which is

y(x) = x + Cx4/1 - 2Cx3

please help. thx.
 
Last edited:
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  • #2
magnifik said:
i am having trouble finding the general solution for the given homogeneous equation:

x2dy = (2y2 - x2) dx

i turned it into the following:
(2y2 - x2) dx - x2 dy = 0
then i used substitution of y = xv and got
(2(xv)2 - x2 - x2v) dx - x3 dv = 0
then i turned this into the following ... i think this may be the part i did wrong
(2v2 - 1 - v) dx - x dv = 0
then the integrating factor was
1/x(2v2 - 1 - v)
so...
dx/x - dv/(2v2 - 1 - v) = 0
i am stuck here. i know the first part is ln x, but I'm not sure if the second part is [ln (2v2 - 1 - v)]/(4v - 1)...if this part is right then i am stuck again here. i don't know how to get to the final solution which is

y(x) = x + Cx4/1 - 2Cx3

please help. thx.

Better if you write your final solution as

[tex]y(x) = \frac{x+Cx^4}{1-2Cx^3}[/tex]
 
  • #3
that doesn't help me :\
 

1. What is a homogeneous equation?

A homogeneous equation is a type of differential equation in which all terms can be expressed as a function of the dependent variable and its derivatives. This means that there is no independent variable in the equation.

2. What is the general solution for a homogeneous equation?

The general solution for a homogeneous equation is a function that satisfies the equation for all possible values of the variables. It is typically expressed in terms of a constant, known as the arbitrary constant, which can take on any value.

3. How do you find the general solution for a homogeneous equation?

To find the general solution for a homogeneous equation, you can use the method of separation of variables, substitution, or the method of undetermined coefficients. These methods involve solving the equation and then incorporating the arbitrary constant into the final solution.

4. Can a homogeneous equation have multiple solutions?

Yes, a homogeneous equation can have infinitely many solutions. This is because the arbitrary constant in the general solution can take on any value, resulting in a different solution for each value.

5. What is the importance of the general solution for a homogeneous equation?

The general solution for a homogeneous equation is important because it allows us to find all possible solutions to the equation. It also serves as a foundation for finding specific solutions that satisfy given initial conditions. Additionally, the general solution can be used to solve more complex differential equations through the method of superposition.

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