power series

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power series

A mathematician writes a power series on the chalkboard.

Definition

Noun: 1. A mathematical expression: A power series is an infinite series of terms. Each term consists of a constant coefficient multiplied by a variable raised to a successively increasing non-negative integer power (e.g., x⁰, x¹, x², x³...). It is a fundamental tool in calculus and analysis for representing functions.

Usage

The term "power series" is used to describe a specific type of mathematical series. It is typically followed by a phrase specifying the variable and the center of the series. * It is often used in the context of convergence, where one discusses the interval or radius within which the series converges to a function. * Common verbs used with it include: expand a function into a power series, find the power series for a function, determine the convergence of a power series.

Examples
  • The power series expansion of the exponential function eˣ is 1 + x + x²/2! + x³/3! + ...
  • A Taylor series is a specific type of power series.
  • The function 1/(1-x) can be represented by the geometric power series Σ xⁿ for |x| < 1.
  • Analyzing the radius of convergence is crucial when working with a power series.
Advanced Usage
  • Formal power series: In algebra, a power series may be treated without concern for convergence, focusing solely on its algebraic properties.
  • Power series solution: A method for solving differential equations by assuming the solution can be written as a power series and solving for the coefficients.
Variants and Related Words
  • Taylor series (n.): A power series that represents a function and is constructed from the function's derivatives at a single point.
  • Maclaurin series (n.): A Taylor series centered at zero.
  • Series expansion (n.): The general expression of a function as an infinite sum of terms, which may be a power series.
  • Coefficient (n.): The constant factor multiplying the variable in each term of a power series.
Synonyms
  • Infinite series (in a general mathematical context, though not all infinite series are power series).
Related Concepts (Mathematical Context)
  • Radius of convergence: A non-negative real number that represents the distance from the center within which the power series converges.
  • Interval of convergence: The set of all real numbers for which the power series converges.
  • Analytic function: A function that can be locally expressed as a convergent power series.
power series

A mathematician writes a power series on the chalkboard.

Noun
  1. the sum of terms containing successively higher integral powers of a variable