E

E, letter of the alphabet

E, fifth letter of the alphabet. It is a usual symbol for a mid-front vowel, such as ĕ in the English step. A mid-front vowel was represented by Greek epsilon [Gr.,=e without the aspirate], to which E corresponds in form and place (see also H). English ē is pronounced as a diphthong of ĭ and y. In musical notation E represents a note in the scale.

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e, in mathematics

e, in mathematics, irrational number occurring widely in mathematics and science, approximately equal to the value 2.71828; it is the base of natural, or Naperian, logarithms. The number e is defined as the limit of the expression (1+1/n)ⁿ as n becomes infinitely large, or In 1873 the French mathematician C. Hermite proved that e was transcendental, i.e., not a root of any algebraic equation; this proof constituted a great contribution to the growth of mathematics. The number e is also known as Euler's number, for Leonhard Euler, who discovered the famous formula e^iπ=−1, where i=−1, thus expressing the relationship between the numbers e, i, and π. The exponential function e^x, often written exp(x), occurs in various applications ranging from statistics to nuclear physics.

Bibliography

See study by E. Maor (1994).

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E

(1) See exponent.

(2) (Electronic) "E" with or without the hyphen (e or e-) is used as a word prefix in order to connote the electronic or Internet version of a physical object or activity: mail becomes e-mail, book becomes e-book, etc. Although "e" terms are often written without the hyphen (dash), we use it in this encyclopedia for readability; for example, "e-commerce" is easier to recognize and verbalize than "ecommerce."

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e

(mathematics)

The base of the natural logarithms; the number defined by the equationapproximately equal to 2.71828.

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E

(electricity)

electric-field vector

(science and technology)

exa-

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class A, B, C, D, E, F

A classification applied to fire doors, fire windows, roof coverings, interior finishes, places of assembly, etc., to indicate gradations of fire safety. See fire-endurance, fire-door rating.

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E

Symbol for “90° elbow.”

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1.		E - An extension of C++ with database types and persistent objects. E is a powerful and flexible procedural programming language. It is used in the Exodus database system. See also GNU E. ftp://ftp.cs.wisc.edu/exodus/E/. ["Persistence in the E Language: Issues and Implementation", J.E. Richardson et al, Soft Prac & Exp 19(12):1115-1150 (Dec 1989)].
2.	(language)	E - A procedural language by Wouter van Oortmerssen with semantics similar to C. E features lists, low-level polymorphism, exception handling, quoted expressions, pattern matching and object inheritance. Amiga E is a version for the Amiga.

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E 

(in Russian, Napier number), the limit of the expression [1 + (1/n)]ⁿ as n increases without bound:

It is the base of the natural system of logarithms. The number e is a transcendental number; this fact was first proved in 1873 by C. Hermite. Naming the number e after J. Napier is not entirely valid. (See.)