I have a question about a/the in mathematics.

I would like to say that x=1 is a/the root of the polynomial (x-1)(x-2).

There are two roots of this polynomial, that is, x=1,2. So x=1 is "a" root of the polynomial? Or should it be "the"?

  • 2
    If there is more than one, use either a or one.
    – J.R.
    Jan 2, 2017 at 19:52
  • @J.R. Thank you. If we don't know how many roots are there, should I use "a" root?
    – Eng
    Jan 2, 2017 at 19:54
  • 1
    @Eng I would suggest that if you don't know whether other roots exist, that by default to use "a". "The", being the definite article, presupposes that you know there to be only one.
    – WS2
    Jan 2, 2017 at 20:36
  • Your question about how to express things in math is answered here: mathworld.wolfram.com/PolynomialRoots.html
    – Lambie
    Jan 2, 2017 at 21:43

2 Answers 2


As J.R. mentions in his comment, if there is more than one something in a list you can either say "a [something]" or "one of the [somethings]"

Goodfellas is a Martin Scorsese film.

Goodfellas is one of Martin Scorsese's films.

So "1" is either "a root" or "one of the roots" of the equation.


Use "the" when there is only one root. Use "a" when there is more than one root, or you don't know the exact number of roots.

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