f ( x ) = ∑ n = 0 ∞ [ a n c o s ( 2 π n x T ) + b n s i n ( 2 π r x T ) ] {\displaystyle f(x)=\sum _{n=0}^{\infty }\left[a_{n}cos\left({\frac {2\pi nx}{T}}\right)+b_{n}sin\left({\frac {2\pi rx}{T}}\right)\right]}
la terminoj a n {\displaystyle a_{n}} e b n {\displaystyle b_{n}} nomatas koeficioj (?) de Fourier kaj kalkulendas tiel:
a n = 2 T ∫ 0 T f ( x ) c o s ( 2 π n x T ) d x {\displaystyle a_{n}={\frac {2}{T}}\int _{0}^{T}f(x)cos\left({\frac {2\pi nx}{T}}\right)dx}
b n = 2 T ∫ 0 T f ( x ) s i n ( 2 π n x T ) d x {\displaystyle b_{n}={\frac {2}{T}}\int _{0}^{T}f(x)sin\left({\frac {2\pi nx}{T}}\right)dx}
![{\displaystyle f(x)=\sum _{n=0}^{\infty }\left[a_{n}cos\left({\frac {2\pi nx}{T}}\right)+b_{n}sin\left({\frac {2\pi rx}{T}}\right)\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/373a10667936df77a0b7f799c5fd013d12ee8a9e)
e 
nomatas
koeficioj (?) de Fourier kaj kalkulendas tiel:
