Trigonometric series
= Trigonometric series
{title2=$a_0/2+\sum_{n\geq1}(a_n\cos nx+b_n\sin nx)$}
A <series> whose terms are multiples of <sines> and <cosines> of integer multiples of a variable. A <Fourier series> is the special case with <coefficients> extracted from a specified <function> by <integration>.