The plus and minus sign ( and - ) are the mathematical symbols used to represent positive and negative meanings as well as addition and subtraction operations. Its use has expanded to many other meanings, roughly the same. Plus and minus are Latin terms meaning "more" and "less," respectively.
Video Plus and minus signs
Histori
Although the signs now appear to be unfamiliar with alphabetical figures or Hindu-Arabic numbers, they are not too old. The Egyptian hieroglyphic sign for the addition, for example, resembles a pair of feet walking in the direction in which the text was written (Egypt can be written both from right to left or left to right), with a reverse mark indicating reduction:
Nicole Oresme's texts from the 14th century show what might be one of the earliest uses of the "" plus sign.
In Europe at the beginning of the 15th century, the letters "P" and "M" were generally used. Symbols (P with line p? for piÃÆ'¹ , that is, plus, and M with line m? for meno , that is, minus) appeared for the first time in the mathematical compendium of Luca Pacioli, Summa de arithmetica, geometria, proportioni et proportionalitÃÆ' , first printed and published in Venice in 1494. The is a Latin simplification "et" (proportional to ampersand & amp; ). The - can be derived from a tilde written above m when used to indicate subtraction; or may come from a shortened version of the letter m itself. In 1489 his treatise Johannes Widmann refers to the symbol - and as minus and mer (Modern German mehr ; "more"): "is - ist , das ist reduced, und das ist das mer ". They are not used for addition and subtraction here, but to show a surplus and a deficit; Their first use in their modern sense appeared in a book by Henricus Grammateus in 1518.
Robert Recorde, the designer of the same sign, introduced the pluses and minuses to England in 1557 at The Whetstone of Witte: "There are two other commonly used signs that are first made so and betokeneth more: others are made - and at stake. "
Maps Plus and minus signs
Added flag
The plus sign ( ) is an additional binary operator, as in 2 3 = 5. It can also function as a unary operator leaving its operand unchanged ( x means equal to < i> x ). This notation can be used when it is desired to emphasize the positivity of numbers, especially when contrasting with negatives (5 versus -5).
The plus sign can also indicate many other operations, depending on which mathematical system is being considered. Many algebraic structures have several operations called, or equivalent, additions. It is conventional to use the plus sign to indicate only commutative operations. In addition, the symbolism has been extended to very different operations; plus can also mean:
- exclusive or (usually written?): 1 1 = 0, 1 0 = 1
- logical disjunction (usually written?): 1 1 = 1, 1 0 = 1
Minus sign
The minus sign ( - ) has three main uses in math:
- Reduction operators: Binary operators to indicate reduction operations, as in 5Ã,-3Ã, = Ã, 2. Reduction is the opposite of addition.
- Right in front of the number (numeric literal) and when it's not a reduction operator it means a negative number. For example -5 is negative 5.
- The unary operator acts as an instruction to replace the operand with its additive inverse. For example, if x is 3, then - x is -3, but if x is -3, then - x < is 3. Similarly, - (- 2) equals 2. Above is a special case for this.
These three uses can be referred to as "minus" in everyday conversation. In most English-speaking countries, -5 (for example) is usually pronounced "minus five", but in modern US usage, this is usually pronounced "negative five"; Here, "minus" can be used by speakers born before 1950, and is still popular in some contexts, but "negative" is usually taught as the only correct reading. Furthermore, some textbooks in the United States encourage - x to be read as "the opposite of x " or "inverse additive x " to avoid an impression that - x is always negative.
In some contexts, different flying machines are used for this meaning; eg in APL computer languages ​​and expression languages ​​used by the Texas Instruments chart calculator (definitely at least the initial model includes TI-81 and TI-82) the raised minus sign is used in negative numbers (as in 2Ã-5 indicates - 3), but such use is rare.
In mathematics and most programming languages, the rules for the sequence of operations mean that -5 2 is equal to -25: Strength binding is stronger than minus unary, which binds stronger than multiplication or division. However, in some programming languages ​​and Microsoft Excel in particular, the most non-binding operator is strongest, so in that case -5 ^ 2 is 25 but 0-5 ^ 2 is -25.
Use in basic education
Some elementary school teachers use plus and minus signs that increase before the numbers show positive or negative numbers. For example, subtracting -5 from 3 can be read as "three positive take negative 5" and displayed as
- 3 - - 5 being 3 5 = 8,
or even as
Use as a qualifier
In the assessment system (such as the check mark), the plus sign shows a higher level one level and the minus sign is lower. For example, B- ("B minus") is one class lower than B. Sometimes it is expanded to two plus or minus marks; for example A is two higher values ​​than A.
Positive and negative are sometimes abbreviated as ve and-ve.
In math, one side of x -> a means x near a of right, and x -> a - means x close to a For example, when calculating what x -1 is when x is close to 0, because x -1 ->? when x -> 0 but x -1 -> -? when x -> 0 - .
Blood type is often qualified with plus or minus to indicate whether or not the Rh factor exists; for example, A means A-type blood with Rh factor is present, while B- means B-type blood with Rh factor is absent.
In music, the augmented chord is represented by a plus sign, although this practice is not universal because there are other methods to spell the chord. For example, "C" is read "C augmented chord". Also used as superscript.
Usage in computing
And the use of normal plus and minus mathematics can be used for a number of other purposes in computing.
Plus and minus signs are often used in the tree view on the computer screen to indicate whether the folder is collapsed or not.
In some programming languages, string concatenation is written "a" "b" , and generates "ab" .
In most programming languages, subtractions and negations are indicated by minus-ASCII-sign characters, - . In APL, an increased minus sign (Unicode U 00AF) is used to indicate a negative number, as in Ã,¯3 . While in J, the negative number is denoted by the underscore, as in _5 .
In C and some other computer programming languages, two plus signs indicate an increase operator and two minus deductions. For example, x means "increase in value of x by one" and x - means "subtraction of value x by one". By extension, "" is sometimes used in computational terminology to signify an increase, as in the C language name.
In a regular expression, "" is used to indicate "1 or more" in the pattern to be matched. For example, "x" means "one or more of the letters x".
There is no negative zero concept in mathematics, but in computation -0 may have a separate representation of zero. In the IEEE floating-point standard, 1Ã,/Ã, -0 is a negative infinity (-?) Whereas 1/, 0 is positive infinity (?).
Other uses
In chemistry, the minus sign (not en dash) is used for a single covalent bond between two atoms, as in the skeletal formula.
The plus and minus sign subscriptions are used as diacritics in the International Phonetic Alphabet to show the articulation of advanced or retractable sound noises.
The minus sign is also used as a letter in the orthography of Dan, Krumen, Karaboro, Mwan, Wan, YaourÃÆ' ©, WÃÆ'¨, Nyabwa and Godià ©. The Unicode character used for the letter tone (U 02D7) differs from the mathematical minus sign.
In the algebraic notation used to record the game of chess, the plus sign () is used to indicate the movement that puts the opponent into the examination. A double plus () is sometimes used to denote multiple checks. A combination of plus and minus signs is used to evaluate displacements (/-,/=, =/, -/).
Character code
The dash-minus (-) is an ASCII/ASCII version of the minus sign, and is duplicated as a hyphen. The length is usually shorter than the plus sign and sometimes at different altitudes. This can be used instead of a true minus sign when the character set is limited to ASCII. Most programming languages ​​and other computer-readable languages ​​do this, because ASCII is generally available as a subset of most character encodings, while U 2212 is a Unicode feature only.
There is a minus commercial (?), Which looks like an obelus, in U 2052 (HTML & amp; # x2052; ).
Entity & amp; plus; is HTML 5.
Alternative plus mark
A Jewish tradition dating from at least the nineteenth century was writing plus using symbols such as inverted T. This practice was adopted into Israeli schools and is still common nowadays in elementary schools (including secular schools) but in schools medium sized enterprises. It is also sometimes used in books by religious authors, but most books for adults use the "international symbol". The reason for this practice is that it avoids writing the "symbol" that looks like a Christian cross. Unicode has this symbol in the U FB29 HEBREW LETTER ALTERNATIVE PLUS SIGN .
See also
- Graft-chimaera for meaning in botanical name
- A list of international dialing prefixes that can represent the amount required to call a country as seen on a phone number
- Table math symbol
- En dash, a sign that looks similar to a subtraction symbol but is used for different purposes
- Asterisk, asterisk? * ? show unstructured linguistic reconstruction, sometimes replaced with superscript plus? ?
References and footnotes
Source of the article : Wikipedia
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