Is this solution valid for the original ODE?

In summary, the conversation is about transforming a 1st order homogeneous ODE into a separable ODE and solving it for y. The individual is having trouble separating the variables and integrating, but eventually reaches the general solution of y=-x/(ln(Ax^2)). They question the correctness of their algebra and bringing y^2 over to the left, but realize they made a mistake in the integration.
  • #1
wtmoore
21
0
[Ok so I have transformed a
1st order homogenous ODE into a seperable ODE. However I am having trouble seperating to get y on it's own.

Here's the problem:

du/dx=(2u^2)/x where u = y/x

du/(2u^2)=dx/x <<can't get tex to work

-1/(4u^2)=ln(x)+C=ln(Ax) <<can't get tex to work

1=-4u^2ln(Ax)

1=-4(y^2/x^2)ln(Ax)

y^2=-4x^2ln(Ax)

y=i2xsqrt(lnAx)


Is this algebra correct? Is this the right solution? I'm not sure about bringing the y^2 over to the left is ok.
 
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  • #2
I realize now, I messed up the integration.

The general solution is:

y=-x/(ln(Ax^2))
 

What is a homogeneous ODE?

A homogeneous ordinary differential equation (ODE) is an equation where all the terms are of the same degree in the dependent variable and its derivatives. In other words, the equation can be written in the form f(x,y,y',y'',...) = 0, where all the terms have the same power of y and its derivatives.

What is a separable ODE?

A separable ordinary differential equation (ODE) is an equation where the dependent variable and its derivatives can be separated into two different functions. In other words, the equation can be written in the form g(y)dy = h(x)dx, where g(y) and h(x) are functions of y and x respectively.

What is the general solution to a homogeneous and separable ODE?

The general solution to a homogeneous and separable ODE is y = Ce^(∫k(x)dx), where C is a constant and k(x) is the function obtained after separating the variables in the ODE.

How do I solve a homogeneous and separable ODE?

To solve a homogeneous and separable ODE, you can follow these steps: 1) Separate the variables and rewrite the equation in the form g(y)dy = h(x)dx; 2) Integrate both sides with respect to their variables; 3) Solve for y and include the constant of integration; 4) Simplify the equation if possible.

What are the applications of homogeneous and separable ODEs?

Homogeneous and separable ODEs are used to model a wide range of phenomena in various fields such as physics, chemistry, biology, economics, and engineering. Some specific examples include population growth, radioactive decay, chemical reactions, and electrical circuits.

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