Editing Polynomial (section)

=== Composition ===
Given a polynomial <math>f</math> of a single variable and another polynomial {{mvar|g}} of any number of variables, the [[function composition|composition]] <math>f \circ g</math> is obtained by substituting each copy of the variable of the first polynomial by the second polynomial.<ref name=Barbeau-2003-pp1-2/>  For example, if <math>f(x) = x^2 + 2x</math> and <math>g(x) = 3x + 2</math> then
<math display = "block"> (f\circ g)(x) = f(g(x)) = (3x + 2)^2 + 2(3x + 2).</math>
A composition may be expanded to a sum of terms using the rules for multiplication and division of polynomials.  The composition of two polynomials is another polynomial.<ref>{{Cite book|last=Kriete|first=Hartje|url=https://books.google.com/books?id=HwqjxJOLLOoC&q=The+composition+of+two+polynomials+is+always+another+polynomial.&pg=PA159|title=Progress in Holomorphic Dynamics|date=1998-05-20|publisher=CRC Press|isbn=978-0-582-32388-9|pages=159|language=en|quote=This class of endomorphisms is closed under composition,}}</ref>
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