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For other uses, see Binomial (disambiguation).

In elementary algebra, a binomial is a polynomial with two terms: the sum of two monomials. It is the simplest kind of polynomial except for a monomial.

[edit] Examples

• <math>a + b \quad </math>
• <math> x+3 \quad </math>
• <math> {x \over 2} + {x^2 \over 2} </math>
• <math> v t - {1 \over 2} g t^2 </math>

The product of a binomial with a factor c is obtained by distributing the monomial:

<math> c (a + b) = c a + c b \ </math>

The product of two binomials a + b and c + d is obtained by distributing twice:

<math> (a + b)(c + d) = (a + b) c + (a + b) d \ </math>

<math> = a c + b c + a d + b d \quad </math>.

The square of a binomial a + b is

<math> (a + b)^2 = a^2 + 2 a b + b^2 \quad </math>

and the square of the binomial a - b is

<math> (a - b)^2 = a^2 - 2 a b + b^2. \quad </math>

The binomial <math> a^2 - b^2 </math> can be factored as the product of two other binomials:

<math> a^2 - b^2 = (a + b)(a - b). \quad </math>

A binomial is linear if it is of the form

<math> a x + b \quad </math>

where a and b are constants and x is a variable.

A complex number is a binomial of the form

<math> a + i b \quad </math>

where i is the square root of minus one.

The product of a pair of linear binomials a x + b and c x + d is:

<math> (a x + b)(c x + d) = a c x^2 + (a d + b c) x + b d \!\,</math>

A binomial a + b raised to the n^th power, represented as

<math> (a + b)^n \quad </math>

can be expanded by means of the binomial theorem or, equivalently, using Pascal's triangle.

[edit] See also

• completing the square
• binomial distribution
• binomial coefficient.
• The list of factorial and binomial topics contains a large number of related links.ca:Binomi

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