# Why call it the Binomial Theorem?

• February 25th 2011, 03:41 AM
Warrenx
Why call it the Binomial Theorem?
Taking Statistics for Economists, and the book refers to the binomial theorem using as:

$(a + b)^n$ where n is # of Bernoulli trials.

I just realized though, although this is considering p(success) and p(failure) as the variables, since outcome space is also a variable, would not a more appropriate moniker be trinomial theorem? I do not know if this qualifies as a question or not, just looking for some clarification on the terminology since number of trials can be potentially infinite.
• February 25th 2011, 04:43 AM
HallsofIvy
a+ b is a binomial because it has two parts. The actual "binomial theorem" has nothing to do with probability and its name has nothing to do with "outcomes".
• February 25th 2011, 02:16 PM
matheagle
trinomial would have three terms, as in

$(a+b+c)^n$