FourierTrigSeries

FourierTrigSeries[expr, t, n] gives the nth-order Fourier trigonometric series expansion of expr in t.

• FourierTrigSeries[expr, {t1, t2, ...}, {n1, n2, ...}] gives the multidimensional Fourier trigonometric series of expr.

Examples

Compute a Fourier trigonometric series:

FourierTrigSeries[t^2, t, 3]

Expand a periodic function:

FourierTrigSeries[SquareWave[t], t, 5]

Please visit the official Wolfram Language Reference for more details.