Problem 85. Remove the polynomials that have positive real elements of their roots.
The characteristic equation for a dynamic system is a polynomial whose roots indicate its behavior. If any of the roots of the polynomial have a positive real part, the behavior of the system will be divergent. Given a cell array of vectors that represent polynomials, remove the ones that have roots with positive real components.
Example:
polyIn = {[1 1],[1 -1]}
polyOut = {[1 1]}
since roots([1 -1]) is 1, a positive number.
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Cris Luengo
on 14 Jul 2012
The test set should contain a polynomial with complex roots where the real part is positive, and a polynomial with a positive and a negative root.
Hans Kramer
on 31 Oct 2018
Too less test cases
Brandon
on 13 Jun 2023
How does [1 1] represent a polynomial? This problem should read "Remove sets with negative numbers" instead.
Christian Schröder
on 14 Jun 2023
@Brandon polynomials in MATLAB are represented by a vector of coefficients; see doc roots.
Aditya Bapat
on 5 Mar 2024
interesting problem
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