Second Order Linear Differential Equation (Non-constant coefficients)

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Homework Help Overview

The discussion revolves around finding the general solution for a second-order linear differential equation with non-constant coefficients, specifically the equation y'' + x(y')^2 = 0.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to simplify the equation using the substitution v(x) = y'(x), but expresses confusion regarding the non-linear term (y')^2. Some participants question whether the presence of the v^2 term is a concern due to its non-linearity, while others suggest that there are methods to address such equations.

Discussion Status

The discussion is active, with participants exploring different interpretations of the problem. One participant indicates familiarity with separation of variables and expresses intent to apply it to the transformed equation, suggesting a potential direction for further exploration.

Contextual Notes

Participants note that their coursework has primarily covered linear differential equations, which may influence their approach to this non-linear problem.

SherlockOhms
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Homework Statement


Find the general solution for the following differential equation:
y'' + x(y')^2 = 0.


Homework Equations


Integration, differentiation...


The Attempt at a Solution


Usually for these sort of DE you could use the substitution v(x) = y'(x) and this would simplify such an equation to a first order DE. The (y')^2 part is throwing me off as this would give the equation:
v(x)' + x(v(x))^2 = 0.
This would be grand if it weren't for the v(x)^2 term. Any ideas on how to get around this? Thanks.
 
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Are you worried about the v^2 term because it makes the eqn non-linear? If so, there are ways to solve such an equation.
 
Yeah. We've only covered linear DE's.
 
DAPOS said:
Yeah. We've only covered linear DE's.

Are you at all familiar with separation of variables?
 
Yeah. So I'll have v'(x) = (-x)(v(x))^2 and I can then separate the variables and solve. Thanks!
 

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