HP 48gII STK, tag, 2`*‚¹, @ UIT@, ‚¹2*„î `, tagged value, which produces:, H(x) = ln(x+1) + exp(-x), Defining and using functions

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`*‚¹Defining and using functions

Users can define their own functions by using the DEFINE command available thought the keystroke sequence „à(associated with the 2key). The function must be entered in the following format:

Function_name(arguments) = expression_containing_argumentsFor example, we could define a simple functionH(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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