# Whats's the name of this theorem about polynomials?

Given a polynomial f with only real coefficients, the zeros of f are conjugates of zeros of f.

(Sorry my English left me, when trying to formulate this theorem.)

So I would like to know how to refer to this theorem in a scientific text.

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Do you mean f is a real valued function or complex valued function? – Hassan Muhammad Mar 9 '12 at 14:47

Complex Conjugate Root Theorem:

In mathematics, the complex conjugate root theorem states that if $P$ is a polynomial in one variable with real coefficients, and $a + bi$ is a root of $P$ with $a$ and $b$ real numbers, then its complex conjugate $a − bi$ is also a root of $P$.

See here.

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From the Wikipedia article: "Thus is follows that the u is back on the attack..." -??? – The Chaz 2.0 Mar 9 '12 at 11:52

You can call it the complex conjugate root theorem.

Depending on the text you might want to just say "recall that ..." or "note that ..." due to triviality.

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