One of the coefficients an or bn of cos (nx)
and sin (nx) respectively in the → Fourier series
representation of a function. They are expressed by: an = (1/π) ∫f(x) cos nx dx, for n≥ 0,
summed over 0 to 2π bn = (1/π) ∫f(x) sin nx dx, for n≥ 1,
summed over 0 to 2π.