Equal+in+number
71Extended real number line — Positive infinity redirects here. For the band, see Positive Infinity. In mathematics, the affinely extended real number system is obtained from the real number system R by adding two elements: +∞ and −∞ (read as positive infinity and negative… …
72F-number — In optics, the f number (sometimes called focal ratio, f ratio, or relative aperture [Smith, Warren Modern Lens Design 2005 McGraw Hill] ) of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; …
73Atomic number — See also: List of elements by atomic number An explanation of the superscripts and subscripts seen in atomic number notation. In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the… …
74Catalan number — For names of numbers in Catalan, see List of numbers in various languages#Occitano Romance. In combinatorial mathematics, the Catalan numbers form a sequence of natural numbers that occur in various counting problems, often involving recursively… …
75Negative number — This thermometer is indicating a slightly negative …
76perfect number — noun : an integer (as 6) the sum of whose divisors including 1 but excluding itself is equal to itself 28, which . 1 + 2 + 4 + 7 + 14, is a perfect number compare imperfect number * * * Math. a positive number that is equal to the sum of all… …
7719 equal temperament — In music, 19 equal temperament, called 19 TET, 19 EDO, or 19 ET, is the tempered scale derived by dividing the octave into 19 equally large steps. Each step represents a frequency ratio of 21/19, or 63.16 cents. Because 19 is a prime number, one… …
78perfect number — Math. a positive number that is equal to the sum of all positive integers that are submultiples of it, as 6, which is equal to the sum of 1, 2, and 3. Cf. abundant number, deficient number. [1350 1400; ME] * * * ▪ mathematics a positive… …
79Complex number — A complex number can be visually represented as a pair of numbers forming a vector on a diagram called an Argand diagram, representing the complex plane. Re is the real axis, Im is the imaginary axis, and i is the square root of –1. A complex… …
800 (number) — Zero redirects here. For other uses, see Zero (disambiguation). 0 −1 0 1 2 3 4 5 6 7 8 …
