Square (math)
In mathematics , the square of a number is a calculation expression ( term ) that expresses the multiplication of this number by itself. The calculation of such a square is called squaring . A superscript two is used as a symbol for the square of a number.
Example: "5 (to) the square" or "5 to the power of 2"
The term "square" comes from geometry : a square in the geometric sense is a rectangle with four sides of equal length and four right angles . The area of such a square is calculated by multiplying the length of the side by itself.
The square of a number is a special case of a power , namely a power with the exponent 2.
The squares of the natural numbers are called square numbers :
However, squares can also be formed from any real or even complex numbers. More generally, the concept of the square can be applied to all internal two-digit relationships written in multiplicative terms, for example to the multiplication of matrices .
The function that each real number its square assigns, is square function and is one of the quadratic functions . Your graph is the so-called normal parabola . The inverse function of the square function restricted to non-negative real numbers is the (square) root function , which assigns each number its square root .
properties
- For properties of the square of natural numbers, see square number .
- The square of a negative number is always the square of its (positive) opposite number:
keyboard
On the German PC keyboard , the ² character is the third assignment on the 2 key and can be entered using the Alt-Gr key. You can often use the two keys Ctrl and Alt instead of Alt Gr . With an Apple keyboard, on the other hand, there is no defined key combination for the ² sign. The ² character and the code number (hexadecimal ) are part of the character coding ISO 8859-1 (or ISO 8859-15 ) and thus also the Unicode block Latin-1, supplement .
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