Plus and minus signs

Plus and minus signs (+ and −) are mathematical symbols used to represent the notions of positive and negative as well as the operations of addition and subtraction. Their use has been extended to many other meanings, more or less analogous. The plus sign "+" denotes addition and positivity, while the minus sign "−" indicates subtraction and negativity.

History

The plus sign is believed to have originated from the Latin word "et," meaning "and." It was first used in its current mathematical context by Swiss mathematician Johann Widmann in 1489. The minus sign is thought to have evolved from a horizontal dash used by merchants in the Middle Ages to indicate subtraction.

Usage in Mathematics

In mathematics, the plus and minus signs are used to indicate basic arithmetic operations of addition and subtraction. They are also used to denote positive and negative numbers, respectively. For example, "+3" denotes a positive three, while "−3" indicates a negative three.

Algebra

In algebra, the plus and minus signs are used to represent the operations of addition and subtraction among variables and constants. They also appear in algebraic expressions and equations, indicating the relationship between different terms.

Calculus

In calculus, these signs play a crucial role in defining the slopes of curves, determining the direction of derivatives, and in the integration of functions with positive and negative areas under the curve.

Usage in Other Fields

Beyond mathematics, the plus and minus signs are used in various contexts:

Electronics

In electronics, the plus and minus signs indicate the polarity of electrical components, such as batteries, where "+" denotes the positive terminal and "−" the negative terminal.

Chemistry

In chemistry, these signs are used to denote the charge of ions; a plus sign indicates a cation (positively charged ion), and a minus sign indicates an anion (negatively charged ion).

Computer Science

In computer science, the plus sign is often used in programming languages to denote addition or concatenation operations, while the minus sign is used for subtraction.

Symbol Variations

The plus and minus signs have variations that are used in specific contexts:

• Plus-minus sign (±): Represents the concept of plus or minus a certain tolerance or indicates the presence of both positive and negative values.
• Minus-plus sign (∓): Used less frequently, this symbol indicates that the sign should be reversed from the preceding sign.

See Also

• Addition
• Subtraction
• Negative number
• Positive number
• Algebra
• Calculus