How Do You Solve Nonautonomous Nonlinear ODEs Like dy/dt = A*y^n + g(t)?

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SUMMARY

The discussion focuses on solving the nonlinear ordinary differential equation (ODE) represented by dy/dt = A*y^n + g(t), where A and n are constants and g(t) is a function of time. It is established that if g(t) is a constant, the equation is autonomous; however, if g(t) varies with time, it becomes nonautonomous. The user can solve the equation for specific cases such as g(t) = 0 or g(t) = constant, but struggles with arbitrary functions of t. The solution's behavior is highly dependent on the form of g(t), with certain choices leading to singularities in the solution.

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  • Understanding of ordinary differential equations (ODEs)
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  • Knowledge of specific functions such as exponential decay (e.g., g(t) = exp(-t/tau))
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  • Explore methods for solving nonlinear ODEs, such as perturbation techniques
  • Research the behavior of solutions to ODEs with varying g(t) using numerical simulations
  • Learn about Lyapunov stability theory to analyze the stability of solutions
  • Investigate specific cases of g(t) and their impact on solution behavior, such as g(t) = sin(t)
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blumfeld0
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I need some help with a differential equation:

dy/dt = A*y^n + g(t)

where A and n are constants that can be any real numbers and g(t) is just
some function of t (e.g., g(t) = exp(-t/tau) or g(t) = constant or g(t) =
0). I think this is a nonlinear ODE.
If g(t) is a constant then it is an "autonomous" equation but if g(t) depends explicitly on t then it is "nonautonomous".
I can solve it if g(t) = 0. and g(t) = constant.
I can't find a solution if g(t) is some arbitrary function of t.

Any help would be much appreciated!
 
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Yes, because of the "y^n" that's a non-linear equation. There is no general way of solving such equations. The solution will depend strongly on exactly what g(t) is.
 
Note for example if you choose A=1, n=2, g(t)=1, then your solution will blow up at a FINITE time. Other choices won't have this "pathological" behaviour, so the precise shape of g is crucial for saying anything particular about the solution of your diff.eq.
 

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