Solution of non-linear set of equations

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Homework Help Overview

The discussion revolves around a set of non-linear differential equations where the number of equations is less than the number of unknowns. The original poster explores the idea of taking derivatives to create additional equations in order to solve the system.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster considers deriving a new set of equations by differentiating with respect to a parameter, questioning whether this approach can yield a solvable system. Other participants discuss the implications of treating derivatives as unknowns and the validity of this method.

Discussion Status

The conversation is ongoing, with participants raising questions about the feasibility of the proposed approach and the need for more specificity in the problem. There is no consensus yet on whether the method is valid or if it constitutes a legitimate solution strategy.

Contextual Notes

The original poster mentions a desire to solve for a specific instance rather than generally, which may influence the interpretation of the problem. There is also a note about the potential for taking additional derivatives to meet the equation count.

mtak0114
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Hi

Consider a set of n non-linear equations and I have m unknowns and n<m, so I don't have enough equations to solve the problem. All the unknowns are parametrized by say t

A possible solution to this that I considered was to take the derivative w.r.t. t and obtain another set of n equations, if 2n > m then I have more equations than unknowns and I these can be solved.

Now will this work?

cheers

M
 
Last edited:
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If you consider the derivatives as well, you get 2n equation is 2m unknowns. Since the derivatives are unknown as well.
 
Sorry I was not clear the equations are really differential equations but I don't want a solution for all t just for 1 so I'm treating each derivative as an unknown. So I have
[tex]f_i(x_i(t),x_i'(t),x_i''(t)...) = 0[/tex] it is possible to have 2n>m+1, if not I just take extra derivatives until it is. Will this work or have I 'cheated'?


cheers

M
 
Maybe if you more specific in the problem you are actually trying solve we could help more. But you can't magically solve an under-determined system by taking derivatives.
 

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