HP 49g+ - Manual (Page 504)

Page 16-30
Thus, c
0
= 1/3, c
1
= ( π⋅i+2)/π 2 , c
2
= ( π⋅i+1)/(2π 2 ).
The Fourier series with three elements will be written as
g(t) ≈ Re[(1/3) + (π⋅i+2)/π 2 ⋅exp(i⋅π⋅t)+ (π⋅i+1)/(2π 2 ) ⋅exp(2⋅i⋅π⋅t)].
A plot of the shifted function g(t) and the Fourier series fitting follows:
The fitting is somewhat acceptable for 0<t<2, although not as good as in the
previous example.