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In the RPN mode, to activate the function enter the argument first, then press
the soft menu key corresponding to the variable name
@@@H@@@
. For example,
you could try:
2`
@@@H@@@
. The other examples shown above can be
entered by using:
1.2`
@@@H@@@
,
2/3`
@@@H@@@
.
Functions can have more than 2 arguments. For example, the screen below
shows the definition of the function
K(
α
,
β
) =
α+β
,
and its evaluation with the
arguments
K(
√
2,
π
),
and
K(1.2,2.3):
The contents of the variable K are: <<
α β
‘
α+β
’ >>.
Functions defined by more than one expression
In this section we discuss the treatment of functions that are defined by two or
more expressions. An example of such functions would be
The HP 49 G provides the function IFTE (IF-Then-Else) to describe such
functions.
The IFTE function
The IFTE function is written as
IFTE(
condition
,
operation_if_true
,
operation_if_false
)
If
condition
is true then
operation_if_true
is performed, else
operation_if_false
is performed. For example, we can write ‘f(x) = IFTE(x>0, x^2-1, 2*x-1)’, to
describe the function listed above. Function IFTE is accessible from the
function catalog (
‚N
). The symbol ‘>’ (greater than) is available as
>
−
<
−
⋅
=
0
,
1
0
,
1
2
)
(
2
x
x
x
x
x
f
