Solving an ODE by the method of Integrating Factors

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Homework Help Overview

The discussion revolves around solving the ordinary differential equation (ODE) y' + y = x y²/3 using the method of integrating factors. Participants express confusion regarding the presence of a term on the right-hand side that is a function of both x and y, which deviates from the standard form typically encountered in examples.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants explore how to manipulate the equation to isolate terms involving x only. Questions arise about the implications of dividing by y²/3 and the resulting form of the equation. There is also an inquiry into the derivative of y raised to the power of 1/3.

Discussion Status

The discussion is ongoing, with participants actively attempting to clarify their understanding of the problem. Some guidance has been provided regarding the manipulation of terms, but no consensus or resolution has been reached yet.

Contextual Notes

Participants are grappling with the challenge of transforming the equation to fit the standard form required for the method of integrating factors, highlighting the complexity introduced by the mixed dependence on both x and y.

1missing
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1. y' + y = x y2/32. The problem states we need to solve this ODE by using the method of integrating factors. Every example I found on the internet involving this method was of the form:

y' + Py = Q

Where P and Q are functions of x only. In the problem I was given however, Q is a function of both x and y. If I try to proceed with the method I end up with:

(d/dx) ex y = x ex y2/3


Annnnd that's where I'm stuck. Am I missing something here or was this problem incorrectly assigned?
 
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So what do you have to do to make the right-hand side a function in ##x## only ?
 
Divide by y2/3 on both sides of the original equation, but then I've got a term in front of the y' and that doesn't seem to get me closer to a solution.
 
What is ##\frac{d(y^{1/3})}{dx}## equal to?
 
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Son of a...I probably would've stared at this thing for a couple of days before I noticed that. That should get me to a solution, let me give it a go.
 
1missing said:
I end up with:
(d/dx) ex y = x ex y2/3

Annnnd that's where I'm stuck. Am I missing something here or was this problem incorrectly assigned?
You could also proceed by noting that the righthand side is equal to ##x e^{x/3} (e^x y)^{2/3}##.
 

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