释义 |
Power SeriesA power series in a variable is an infinite Sum of the form
 | (1) |
where and are Integers, Real Numbers, ComplexNumbers, or any other quantities of a given type.
A Conjecture of Pólya is that if a Function has a Power series with IntegerCoefficients and Radius of Convergence 1, then either the Function isRational or the Unit Circle is a natural boundary.
A generalized Power sum for , 1, ... is given by
 | (2) |
with distinct Nonzero Roots , Coefficients which arePolynomials of degree for Positive Integers , and . The generalized Power sum has order
 | (3) |
For any power series, one of the following is true: - 1. The series converges only for
. - 2. The series converges absolutely for all
. - 3. The series converges absolutely for all
in some finite open interval and diverges if or . At the points and , the series may converge absolutely, converge conditionally, or diverge. To determine the interval of convergence, apply the Ratio Test for Absolute Convergence and solve for . APower series may be differentiated or integrated within the interval of convergence. Convergent power series may bemultiplied and divided (if there is no division by zero).
 | (4) |
Converges if and Diverges if .See also Binomial Series, Convergence Tests, Laurent Series, Maclaurin Series, MultinomialSeries, p-Series, Polynomial, Power Set, Quotient-Difference Algorithm, RecurrenceSequence, Series, Series Reversion, Taylor Series References
Arfken, G. ``Power Series.'' §5.7 in Mathematical Methods for Physicists, 3rd ed. Orlando, FL: Academic Press, pp. 313-321, 1985.Myerson, G. and van der Poorten, A. J. ``Some Problems Concerning Recurrence Sequences.'' Amer. Math. Monthly 102, 698-705, 1995. Pólya, G. Mathematics and Plausible Reasoning, Vol. 2: Patterns of Plausible Inference. Princeton, NJ: Princeton University Press, p. 46, 1954.
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