FourierCoefficient

FourierCoefficient[expr,t,n]

gives the n^(th) coefficient in the Fourier series expansion of expr.

FourierCoefficient[expr,{t1,t2,},{n1,n2,}]

gives a multidimensional Fourier coefficient.

Details and Options

  • The ^(th) coefficient in the Fourier series expansion of is by default given by .
  • The -dimensional Fourier coefficient is given by .
  • In the form FourierCoefficient[expr,t,n], n can be symbolic or an integer.
  • The following options can be given:
  • Assumptions$Assumptionsassumptions on parameters
    FourierParameters{1,1}parameters to define Fourier series
    GenerateConditionsFalsewhether to generate results that involve conditions on parameters
  • The function expr is assumed to be periodic in t with period , except when otherwise specified by FourierParameters.
  • Common settings for FourierParameters include:
  • {1,1}f(t) e-i n tdtdefault settings
    {1,-2Pi}f(t) ei 2π n tdtperiod 1
    {a,b}general setting

Examples

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Basic Examples  (2)

Find the 5^(th) Fourier coefficient:

Find the coefficient of the general term in a Fourier series:

Plot the sequence:

Find the {3,5} Fourier coefficient:

Find the coefficient of the general term:

Plot the absolute value of coefficients:

Scope  (4)

Find the 3^(rd) Fourier coefficient for an exponential function:

General Fourier coefficient for a Gaussian function:

General Fourier coefficients for Abs:

Fourier coefficient for a basis exponential function:

Options  (2)

Assumptions  (1)

Specify assumptions on a parameter:

FourierParameters  (1)

Use a nondefault setting for FourierParameters:

Properties & Relations  (4)

FourierCoefficient is defined by an integral:

Compute the exponential Fourier series using the individual coefficients:

FourierCoefficient is the same as InverseFourierSequenceTransform:

Fourier coefficients for basis exponentials:

Introduced in 2008
 (7.0)