exponential sum

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• Exponential sum — In mathematics, an exponential sum may be a finite Fourier series (i.e. a trigonometric polynomial), or other finite sum formed using the exponential function, usually expressed by means of the function:e(x) = exp(2pi ix).Therefore a typical… …   Wikipedia

• Exponential integral — is a mathematical function of a single argument which has no established notation.DefinitionsFor real values of x , the exponential integral Ei( x ) can be defined as : mbox{Ei}(x)=int { infty}^xfrac{e^t}t,dt., The definition above can be used… …   Wikipedia

• Exponential smoothing — is a technique that can be applied to time series data, either to produce smoothed data for presentation, or to make forecasts. The time series data themselves are a sequence of observations. The observed phenomenon may be an essentially random… …   Wikipedia

• Exponential distribution — Not to be confused with the exponential families of probability distributions. Exponential Probability density function Cumulative distribution function para …   Wikipedia

• Exponential family — Not to be confused with the exponential distribution. Natural parameter links here. For the usage of this term in differential geometry, see differential geometry of curves. In probability and statistics, an exponential family is an important… …   Wikipedia

• Exponential decay — A quantity undergoing exponential decay. Larger decay constants make the quantity vanish much more rapidly. This plot shows decay for decay constants of 25, 5, 1, 1/5, and 1/25 for x from 0 to 5. A quantity is said to be subject to exponential… …   Wikipedia

• exponential function — Math. 1. the function y = ex. 2. any function of the form y = bax, where a and b are positive constants. 3. any function in which a variable appears as an exponent and may also appear as a base, as y = x2x. [1890 95] * * * In mathematics, a… …   Universalium

• Exponential function — The natural exponential function y = ex In mathematics, the exponential function is the function ex, where e is the number (approximately 2.718281828) such that the function ex is its own derivative …   Wikipedia

• Exponential formula — In combinatorial mathematics, the exponential formula (called the polymer expansion in physics) states that the exponential generating function for structures on finite sets is the exponential of the exponential generating function for connected… …   Wikipedia

• Exponential factorial — An exponential factorial is a positive integer n raised to the power of n 1, which in turn is raised to the power of n 2, and so on and so forth, that is, n^{(n 1)^{(n 2) dots . The exponential factorial can also be defined with the recurrence… …   Wikipedia

• Sum-product number — A sum product number is an integer that in a given base is equal to the sum of its digits times the product of its digits. Or, to put it algebraically, given an integer n that is l digits long in base b (with d x representing the x th digit), ifn …   Wikipedia