===== Polynomial function =====
==== Set ====
| @#FF9944: definition  | @#FF9944: $??$ |
| @#FF9944: definition  | @#FF9944: $??$ |

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=== Discussion ===
== Simply quadratic equation ==
$q(x)=x\,x-a\,x$

$q(x)=0 \implies (x=0\lor x=a)$

== A small deviation ==
$p(x)=x\,x-a\,x+b$

$p(x)=0 \implies x=a\cdot\dfrac{1+\epsilon\sqrt{1-\left(\frac{2}{a}\right)^2\cdot b}}{2}, \epsilon=\pm 1$

$\lim_{b\to 0}\sqrt{1-\left(\frac{2}{a}\right)^2\cdot b}=1$

<code>
Series[(1 + \[Epsilon] Sqrt[1 - d])/2, {d, 0, 5}]
</code>

=== Reference ===
Wikipedia: 
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=== Subset of ===
[[Analytic function]]
=== Requirements ===
[[Complex number]]