Nonlinear ODE: Analytical Solution?

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Homework Help Overview

The discussion revolves around a nonlinear first-order ordinary differential equation (ODE) given by \(\frac{dH}{dt}=B-A*(H-Z)^{3/2}\), where B, A, and Z are constants. The original poster has solved the equation numerically and is inquiring about the possibility of obtaining an analytical solution for H(t).

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants explore the transformation \(h = H - Z\) to simplify the ODE, leading to the equation \(h' = b - a h^{3/2}\). There are discussions about the complexity of the solution found using Mathematica, with some expressing uncertainty about deriving a clean expression for H(t).

Discussion Status

The conversation is ongoing, with participants sharing their attempts to manipulate the equation and noting the challenges in finding a manageable analytical solution. There is an acknowledgment that an analytical solution may not exist.

Contextual Notes

Some participants mention the messy nature of the solutions produced by computational tools, indicating potential difficulties in the analytical approach. The original poster's numerical solution is noted, but the focus remains on the analytical aspect.

Pepo
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Nonlinear 1st order ODE

\frac{dH}{dt}=B-A*(H-Z)^{3/2}
where:
B,A and Z are known values

H=f(t); H is function of t




I've already solve this ODE numerically using a 4th order RK routine. But my question is, it is possible to get an analytical solution for H(t)?
 
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first let h = H-Z, then you get

h' = b-ah^(3/2)
 
mathematica finds it messy...
http://www.wolframalpha.com/input/?i=h'(t)+%3D+b-a*(h(t))^(3/2)
 
lanedance said:
first let h = H-Z, then you get

h' = b-ah^(3/2)

lanedance said:
mathematica finds it messy...
http://www.wolframalpha.com/input/?i=h'(t)+%3D+b-a*(h(t))^(3/2)

I have try it plugging it with h=H-Z in mathematica but the solution is a mess. I really don't know how to get an expression for H(t) from this. :-/
 
there may not be one...
 

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