2.6.2.25 Trigonometric Fourier series
condition: Expand the function \( f(x)=\left\{\begin{array}{c}x, \text { for } x<0 \\ \pi+x, \text { for } x>0\end{array}\right. \) on the interval \( (-\pi ; \pi) \) into a Fourier series. Construct a graph of the function and the sum of the Fourier series.
Trigonometric Fourier series - calculation of Fourier coefficients, expansion of functions in cosines and sines, plotting graphs of the sum of the Fourier series using the Dirichlet theorem, as well as graphs of partial sums.