HP 50g Graphing Calculator User Manual
Page 507
Page 16-30
The fitting is somewhat acceptable for 0<t<2, although not as good as in the
previous example.
A general expression for c
n
The function FOURIER can provide a general expression for the coefficient c
n
of
the complex Fourier series expansion. For example, using the same function g(t)
as before, the general term c
n
is given by (figures show normal font and small
font displays):
The general expression turns out to be, after simplifying the previous result,
We can simplify this expression even further by using Euler’s formula for
complex numbers, namely, e
2in
π
= cos(2n
π) + i⋅sin(2nπ) = 1 + i⋅0 = 1, since
cos(2n
π) = 1, and sin(2nπ) = 0, for n integer.
Using the calculator you can simplify the expression in the equation writer
(
‚O) by replacing e
2in
π
= 1. The figure shows the expression after
simplification:
π
π
π
π
π
π
in
in
n
e
n
i
n
n
i
e
i
n
c
2
3
3
2
2
2
2
2
2
3
2
)
2
(
⋅
−
+
+
⋅
+
=