Defining And Using Functions - HP 48gII User Manual

To copy the value of Vm to the stack, select the variable name, and
press ! STK, then, press @ UIT@. For the calculator set to the ALG, the screen
will look like this:
The display shows what is called a tagged value, . In here,
Vm, is the tag of this result. Any arithmetic operation with this number will
ignore the tag. Try, for example:
‚¹2*„î `
which produces:
The same operation in RPN mode will require the following keystrokes (after
the value of Vm was extracted from the constants library):
2`*‚¹

Defining and using functions

Users can define their own functions by using the DEFINE 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 function
H(x) = ln(x+1) + exp(-x)
Suppose that you have a need to evaluate this function for a number of
discrete values and, therefore, you want to be able to press a single button
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