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  2. Probability-generating function - Wikipedia

    en.wikipedia.org/wiki/Probability-generating...

    If X is a discrete random variable taking values x in the non-negative integers {0,1, ...}, then the probability generating function of X is defined as [1] G ( z ) = E ⁡ ( z X ) = ∑ x = 0 ∞ p ( x ) z x , {\displaystyle G(z)=\operatorname {E} (z^{X})=\sum _{x=0}^{\infty }p(x)z^{x},} where p {\displaystyle p} is the probability mass ...

  3. Power series - Wikipedia

    en.wikipedia.org/wiki/Power_series

    The partial sums of a power series are polynomials, the partial sums of the Taylor series of an analytic function are a sequence of converging polynomial approximations to the function at the center, and a converging power series can be seen as a kind of generalized polynomial with infinitely many terms. Conversely, every polynomial is a power ...

  4. Smith chart - Wikipedia

    en.wikipedia.org/wiki/Smith_chart

    Points with suffix P are in the Z plane and points with suffix Q are in the Y plane. Therefore, transformations P 1 to Q 1 and P 3 to Q 3 are from the Z Smith chart to the Y Smith chart and transformation Q 2 to P 2 is from the Y Smith chart to the Z Smith chart. The following table shows the steps taken to work through the remaining components ...

  5. Normal distribution - Wikipedia

    en.wikipedia.org/wiki/Normal_distribution

    For any ⁠ ⁠, the coefficient of ⁠ /! ⁠ in the moment generating function (expressed as an exponential power series in ⁠ ⁠) is the normal distribution's expected value ⁠ [] ⁠. The cumulant generating function is the logarithm of the moment generating function, namely

  6. Bell series - Wikipedia

    en.wikipedia.org/wiki/Bell_series

    In mathematics, the Bell series is a formal power series used to study properties of arithmetical functions. Bell series were introduced and developed by Eric Temple Bell . Given an arithmetic function f {\displaystyle f} and a prime p {\displaystyle p} , define the formal power series f p ( x ) {\displaystyle f_{p}(x)} , called the Bell series ...

  7. Formal power series - Wikipedia

    en.wikipedia.org/wiki/Formal_power_series

    A formal power series can be loosely thought of as an object that is like a polynomial, but with infinitely many terms.Alternatively, for those familiar with power series (or Taylor series), one may think of a formal power series as a power series in which we ignore questions of convergence by not assuming that the variable X denotes any numerical value (not even an unknown value).

  8. Lagrange inversion theorem - Wikipedia

    en.wikipedia.org/wiki/Lagrange_inversion_theorem

    Faà di Bruno's formula gives coefficients of the composition of two formal power series in terms of the coefficients of those two series. Equivalently, it is a formula for the nth derivative of a composite function. Lagrange reversion theorem for another theorem sometimes called the inversion theorem; Formal power series#The Lagrange inversion ...

  9. Log-distance path loss model - Wikipedia

    en.wikipedia.org/wiki/Log-distance_path_loss_model

    is the reference distance, usually 1 km (or 1 mile) for a large cell and 1 m to 10 m for a microcell. [1] is the path loss exponent. is a normal (Gaussian) random variable with zero mean, reflecting the attenuation (in decibels) caused by flat fading [citation needed]. In the case of no fading, this variable is 0.