Problem 85. Remove the polynomials that have positive real elements of their roots.

Created by Cody Team

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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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Last Solution submitted on Oct 03, 2025

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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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Problem 85. Remove the polynomials that have positive real elements of their roots.

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Problem 85. Remove the polynomials that have positive real elements of their roots.

Solution Stats

Last 200 Solutions

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Problem Recent Solvers1724

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More from this Author96

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