Compare these expressions with the one given earlier in the definition of
the Laplace transform, i.e.,
and you will notice that the CAS default variable X in the equation writer
screen replaces the variable s in this definition. Therefore, when using the
function LAP you get back a function of X, which is the Laplace transform of
f(X).
Example 2 – Determine the inverse Laplace transform of F(s) = sin(s). Use:
The calculator returns the result: 'X e
-x
x e
.
Fourier series
A complex Fourier series is defined by the following expression
where
1
T
∫
) (
c
f
t
n
T
0
Function FOURIER
Function FOURIER provides the coefficient c
Fourier series given the function f(t) and the value of n.
FOURIER requires you to store the value of the period (T) of a T-periodic
function into the CAS variable PERIOD before calling the function. The
function FOURIER is available in the DERIV sub-menu within the CALC
menu ( „Ö ).
Page 14-5
) (
(
)
L
f
t
F
s
'1/(X+1)^2' ` ILAP
∑
f
) (
t
c
n
2
i
n
exp(
T
∫
) (
st
f
t
e
dt
0
-X
', meaning that L
2
in
t
exp(
),
n
T
)
,
t
dt
n
of the complex-form of the
n
,
-1
2
{1/(s+1)
} =
,...,
, 2
1
0 ,
1 ,
2 ,
,...
The function
.