Fourier Coefficient Calculator

Calculate Fourier series coefficients and evaluate series approximations for periodic functions.

Input

Square wave: f(x) = sgn(sin(πx/L))

Period = 6.2832, L = 3.1416

Fourier Series at x = 1.5708

1.0630539691

Actual: 1.000000, Error: 6.3054e-2

Fourier Coefficients

naₙbₙ|cₙ|
00.0000000.0000000.000000
10.0000001.2732401.273240
20.0000000.0000000.000000
30.0000000.4244130.424413
40.0000000.0000000.000000
50.0000000.2546480.254648
60.0000000.0000000.000000
70.0000000.1818910.181891
80.0000000.0000000.000000
90.0000000.1414710.141471
100.0000000.0000000.000000

Convergence

S_1=1.273S_2=1.273S_3=0.849S_4=0.849S_5=1.103S_6=1.103S_7=0.922S_8=0.922S_9=1.063S_10=1.063

Parseval's Theorem

Σ(aₙ² + bₙ²) ≈ 1.919210

Fourier Series

Formula

f(x) = a₀/2 + Σ(aₙcos(nπx/L) + bₙsin(nπx/L))

Applications

  • Signal processing
  • Heat equation solutions
  • Vibration analysis