2.6.2.39 Trigonometric Fourier series
condition: On a given interval, expand the function into a Fourier series in cosines: \[ f(t)=3^{-t}, \quad-1 \leq t \leq 0 \]
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.