Letters Used to Name Integers and Irrational NumbersDate: 1/13/96 at 9:25:46 From: Barbara R Carpenter Subject: integers Dr. Math My students wonder why the set on integers is referred to as J. i.e. J = {... -3, -2, -1. 0, 1, 2, 3, ...} doesn't it make sense to refer to it as I? And what letter is used to name the set of irrational numbers? Thanks, The Elementary Students at Suomi College Date: 3/1/96 at 20:0:58 From: Doctor Jodi Subject: Re: integers Hi Barbara! I wondered why we called integers "j" for a long, long time when I was younger. Mathematicians like use letters to refer to things. And we seem to get used to using particular letters so that we remember what they stand for more quickly. Mathematicians use the letter i - for imaginary - to refer to the square root of negative one. -Doctor Jodi, The Math Forum Date: 3/2/96 at 11:27:15 From: Doctor Ken Subject: Re: integers Hello! If I were you, I'd be confused too! I can't see any reason why the set of integers would be called J. But actually, I've never seen it called J. Most mathematicians (when they're talking to each other, anyway) use Z to refer to the set of integers. The reason for that is the German word "zahlen" which means "to count." And "Zahl" means "number." The rational numbers are called Q, probably for "quotient." I don't think I've ever heard a name for the set of irrational numbers, but that's okay, people refer to them as R-Q (R is the set of real numbers). -Doctor Ken, The Math Forum |
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