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A little bit broader than you asked for, but:

A dynamic control system is modeled by a set of dynamic equations, usually expressed as partial derivatives. To analyze the behaviour of such a system, the equation is solved or approximated in the complex time domain. The relevant part of the solution is where the real part of time is positive, i.e. the right-half plane.

A pole is a coordinate for which the dynamic equations have no solution (y = 1/z has a pole at z=0), which results in undefined or uncontrolled behaviour.

(also see https://en.wikipedia.org/wiki/Zeros_and_poles)



Honestly, this comment better than the article.


I don't think a vague but more precise mathematical explanation of the terms zero and pole are even that difficult to understand, x has a zero, 1/x has a pole, people kind of know what that means if you look at a graph of a pole, I don't think a rigorous definition of pole is that far off - a pole of f is just a zero of 1/f.

Instead we get waffle like:

> Again roughly speaking, zeros describe mathematically how a system reacts to some input in the short term, while poles describe how a system reacts in the long term.

I know it's "roughly" speaking, but isn't it too rough?




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