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  2. Exponential sum - Wikipedia

    en.wikipedia.org/wiki/Exponential_sum

    An example of an incomplete sum is the partial sum of the quadratic Gauss sum (indeed, the case investigated by Gauss). Here there are good estimates for sums over shorter ranges than the whole set of residue classes, because, in geometric terms, the partial sums approximate a Cornu spiral; this implies massive cancellation.

  3. Gamma function - Wikipedia

    en.wikipedia.org/wiki/Gamma_function

    The gamma function then is defined in the complex plane as the analytic continuation of this integral function: it is a meromorphic function which is holomorphic except at zero and the negative integers, where it has simple poles. The gamma function has no zeros, so the reciprocal gamma function ⁠ 1 / Γ(z) ⁠ is an entire function.

  4. List of mathematical series - Wikipedia

    en.wikipedia.org/wiki/List_of_mathematical_series

    This list of mathematical series contains formulae for finite and infinite sums. It can be used in conjunction with other tools for evaluating sums. Here, is taken to have the value

  5. Exponential function - Wikipedia

    en.wikipedia.org/wiki/Exponential_function

    In mathematics, the exponential function is the unique real function which maps zero to one and has a derivative equal to its value. The exponential of a variable ⁠ x {\displaystyle x} ⁠ is denoted ⁠ exp ⁡ x {\displaystyle \exp x} ⁠ or ⁠ e x {\displaystyle e^{x}} ⁠ , with the two notations used interchangeably.

  6. Error function - Wikipedia

    en.wikipedia.org/wiki/Error_function

    where p = 0.3275911, a 1 = 0.254829592, a 2 = −0.284496736, a 3 = 1.421413741, a 4 = −1.453152027, a 5 = 1.061405429 All of these approximations are valid for x ≥ 0 . To use these approximations for negative x , use the fact that erf x is an odd function, so erf x = −erf(− x ) .

  7. Summation - Wikipedia

    en.wikipedia.org/wiki/Summation

    In mathematics, summation is the addition of a sequence of numbers, called addends or summands; the result is their sum or total.Beside numbers, other types of values can be summed as well: functions, vectors, matrices, polynomials and, in general, elements of any type of mathematical objects on which an operation denoted "+" is defined.

  8. Gamma distribution - Wikipedia

    en.wikipedia.org/wiki/Gamma_distribution

    The gamma distribution is the maximum entropy probability distribution (both with respect to a uniform base measure and a / base measure) for a random variable X for which E[X] = αθ = α/λ is fixed and greater than zero, and E[ln X] = ψ(α) + ln θ = ψ(α) − ln λ is fixed (ψ is the digamma function). [5]

  9. Exponentiation - Wikipedia

    en.wikipedia.org/wiki/Exponentiation

    Raising 0 to a negative exponent is undefined but, in some circumstances, it may be interpreted as infinity (). [ 26 ] This definition of exponentiation with negative exponents is the only one that allows extending the identity b m + n = b m ⋅ b n {\displaystyle b^{m+n}=b^{m}\cdot b^{n}} to negative exponents (consider the case m = − n ...