Multiplication sign
From Wikipedia, the free encyclopedia
The multiplication sign is the symbol × (multiplication sign is the preferred Unicode name for the codepoint represented by that glyph). The symbol is similar to the lowercase letter x but is a more symmetric saltire, and has different uses.
In mathematics, the symbol × (read as times or multiplication sign) is primarily used to denote the
- multiplication of two numbers (except in computer languages, where the asterisk (*) is usually used instead)
- cross product of two vectors
- Cartesian product of two sets
- multiplication and the sign function, as an APL function symbol
The × symbol for multiplication was introduced by William Oughtred in 1631.[1]
In biology, the multiplication sign is used in a botanical hybrid name, where it is read as cross.
The × symbol is U+00D7 in Unicode. It is represented by × and × in HTML, and by \times in TeX. The multiplication sign should not be confused with the ⨯ (U+2A2F "vector or cross product") symbol which is used for an entirely different purpose (see Cross product).
The × was chosen as the multiplication sign for religious reason to represent the cross.[2]
Unfortunately, The × symbol can be confused with the common mathematical variable x. Thus, an alternate symbol for the multiplication of two numbers is in common use: the interpunct, "·".
[edit] References
- ^ Florian Cajori (1919). A History of Mathematics. Macmillan. http://books.google.com/books?id=bBoPAAAAIAAJ&pg=PA157&dq=inauthor:cajori+william-oughtred+multiplication.
- ^ Stallings, L. (2000). "A Brief History of Algebraic Notation". School Science and Mathematics 100 (5): 230–235. ISSN 00366803.
[edit] External links
- http://www.eki.ee/letter/chardata.cgi?ucode=00D7
- http://www.fileformat.info/info/unicode/char/00d7/index.htm (the general multiplication sign)
- http://www.fileformat.info/info/unicode/char/2a2f/index.htm (the cross product sign)
