First order nonlinear ordinary differential equation

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Homework Help Overview

The discussion revolves around a first-order nonlinear ordinary differential equation of the form y' + Ay² = B, where A and B are constants. The original poster expresses uncertainty about how to approach solving this equation, particularly given their background in basic linear differential equations.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to differentiate the equation, leading to a second-order form, but finds it complicated. Some participants suggest rewriting the equation in a separable form and integrating, while others confirm its separability and outline the need for algebraic manipulation to solve for y in terms of x.

Discussion Status

Participants are exploring different methods to approach the problem, with some offering guidance on how to rearrange the equation for integration. The original poster acknowledges the suggestions and expresses confidence in tackling the next steps independently.

Contextual Notes

The original poster indicates a lack of experience with nonlinear differential equations and seeks foundational knowledge to assist in solving the problem. There is an implied need for further study in differential equations, as suggested by participants.

MadMathMan
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Homework Statement



y' + Ay2 = B

A & B are constants and y is a function of x

Find the general solution to the differential equation. (Find y(x)).

Homework Equations





The Attempt at a Solution



This differential equation came up when I was trying to solve a problem in physics. I have just learned to solve basic linear differential equations from high school and don't know how to start solving this or even if it's solvable without a computer. If somebody could give me a push in the right direction or tell me what I could study to be able to solve it, it would have been very nice :)

The only thing I've tried is differentiating it with respect to x, and getting this:

y'' + 2Ayy' = 0

I don't find this any easier because I have the y×y' there. So, any help would be nice ;)
 
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Write the ODe in the following way:
[tex] \frac{dy}{dx}=B-Ay^{2}[/tex]
This equation is separable, divide by [tex]B-Ay^{2}[/tex] and integrate

Mat
 
This one is "separable" - which means it's solvable using integration. Rearrange to get
[tex] \frac{dy}{B-Ay^2} = dx,[/tex]
and do two integrals. There will be significant algebraic rearrangement involved to solve for y in terms of x.

You should probably reference a differential equations book.
 
Thanks for the answers!
That was really less painful than I expected :-p Don't know why I didn't think of that :rolleyes:
Next problem now is solving the integral, but I think I should be able to do that myself
 

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