A second order nonlinear ODE? Whoa

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Homework Help Overview

The discussion revolves around a second-order nonlinear ordinary differential equation (ODE) given by \(\frac{d^{2}y}{dt^{2}} + t^{2} \frac{dy}{dt} + y^{2} = 0\) with initial conditions \(y(0)=0\) and \(y'(0)=0\). Participants are exploring the solvability of the equation and questioning whether there might be a typo in the problem statement.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • One participant attempts to substitute \(v=y'\) but finds it unhelpful. Others question the implications of the initial conditions and suggest considering simpler functions that satisfy the initial conditions. There is also speculation about the possibility of a typo in the equation.

Discussion Status

Participants are actively engaging with the problem, with some suggesting that the problem may be simpler than initially perceived. Hints have been provided that encourage inspection of potential solutions, and there is recognition of the role of initial conditions in determining the nature of the solution.

Contextual Notes

There is uncertainty regarding the correctness of the equation as stated, particularly the term \(y^{2}\), which some participants speculate could be a typo. The discussion also touches on the implications of the initial conditions for the existence and uniqueness of solutions.

sciboinkhobbes
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Homework Statement


I'm not sure if this is actually solvable, or a typo on my homework... but here's the problem in question:

Solve the ODE:
\frac{d^{2}y}{dt^{2}} + t^{2} \frac{dy}{dt} + y^{2} = 0, y(0)=0, y'(0)=0Attempt at solution
I've been stumped on where to even start with this one, but I attempted to substitute v=y'. That didn't get me very far though, so any tips on where to start would be appreciated!

Typo-wise, I'm also wondering if perhaps the y^{2} in the equation is actually just supposed to be a y... which would make it significantly easier.
 
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This looks almost like a trick question...given your initial conditions, what will y''(0) be? What then would you expect y'(0+dt) and y(0+dt) to be?...Do you see where this is going?
 
sciboinkhobbes said:

Homework Statement


I'm not sure if this is actually solvable, or a typo on my homework... but here's the problem in question:

Solve the ODE:
\frac{d^{2}y}{dt^{2}} + t^{2} \frac{dy}{dt} + y^{2} = 0, y(0)=0, y'(0)=0


Attempt at solution
I've been stumped on where to even start with this one, but I attempted to substitute v=y'. That didn't get me very far though, so any tips on where to start would be appreciated!

Typo-wise, I'm also wondering if perhaps the y^{2} in the equation is actually just supposed to be a y... which would make it significantly easier.
Actually, this whole problem is trivial! What is the easiest possible function that satisfies y(0)= 0, y'(0)= 0? Can you show that that is a solution to the differential equation? And, of course, by the "existence and uniqueness" theorem, it is the solution.
 
Ooooooh...

Okay, that makes perfect sense! I was making it out to be a lot harder than it was, and wasn't trying to solve it by inspection, but after looking at it with your hints, it's very clear.

Thank you both!

Just out of curiosity, if the initial conditions weren't given, would it be solvable analytically?
 

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