A function that varies as the power of another quantity. If y=ax, y varies exponentially with x. The function ex, also written as exp(x), is called the exponential function (see e). It is equal to the sum of the exponential series, i.e.
A function of a real variable defined for all real x by the sum to infinity of the (convergent) series
The notation reflects the index property that ex×ey=ex+y. The notation ‘exp(x)’ is sometimes used for ex, particularly when x is a complicated algebraic expression. The number e is given by the above series with x = 1, so
The exponential and natural logarithm functions are related by exp (ln x) = x for x>0 and ln (ex) = x for all values of x.
- hand controller
- hand geometry biometrics
- hand-held computer
- Hand-Held Device Markup Language
- handhold
- H and K lines
- handle
- hand lens
- handover
- handshake
- handshake protocol
- handshaking lemma
- hands off
- hands on
- hand tracking
- hang
- hanging rootogram
- hanging valley
- hanging wall
- Hang Seng index
- hang-up
- Hanle effect
- Hannan, Edward James (1921–94)
- Hannan Medal
- Hannan–Quinn criterion