Examples of Fourier series development
Fourier series

Proposition 3

Let f ∊ L ¹ , a _n = a _n (f ) , b _n = b _n (f ) , c _n = c _n (f ).

a)If fis even, we have b _n = 0

and : $S_N\left(f,\mathrm{\hspace{0.17em}}x\right)=\frac{a_0}{2}+$