An Etymological Dictionary of Astronomy and Astrophysics

The complex notation for the → Fourier series of a function f(x). Using → Euler’s formulae, the function can be written in cimplex form as

f(x) = Σ c_n e^inx (summed from -∞ to ∞), where the → Fourier coefficients are

c_n = (1/2π)∫ f(x) e^-inx dx (integral from -π to +π).

See also: → complex; → Fourier series.