HP 49g+ - Manual (Page 155)

Page 3-33
Function TDELTA
Function TDELTA(T
0
,T
f
) yields the temperature increment T
f
– T
0
. The result is
returned with the same units as T
0
, if any. Otherwise, it returns simply the
difference in numbers. For example,
The purpose of this function is to facilitate the calculation of temperature
differences given temperatures in different units. Otherwise, it’s simply
calculates a subtraction, e.g.,
Function TINC
Function TINC(T
0
, ∆T) calculates T
0
+DT. The operation of this function is similar
to that of function TDELTA in the sense that it returns a result in the units of T
0
.
Otherwise, it returns a simple addition of values, e.g.,
Defining and using functions
Users can define their own functions by using the DEF command available
thought the keystroke sequence „à (associated with the 2 key). The
function must be entered in the following format:
Function_name(arguments) = expression_containing_arguments
For example, we could define a simple functionH(x) = ln(x+1) + exp(-x).