hp40g+.book Page 13 Friday, December 9, 2005 1:03 AM

How to enter infix functions

How to enter prefix functions

select the entire expression and press , you obtain:

 

4

 

--

 

5

However, if you type:

 

∞

 

 

1

∑ K--------------------------⋅ (K + 1)

K = 1

 

select the entire expression and press , you obtain 1.

An infix function is one that is typed between its arguments. For example, AND, and MOD are infix functions.You can either:

•type them in Alpha mode and then enter their arguments, or

•select them from a CAS menu or by pressing an appropriate key, provided that you have already written and selected the first argument.

You move from one argument to the other by pressing

and . The comma enables you to write a complex number: when you type (1,2), the parentheses are automatically placed when you type the comma. If you want to type (–1,2), you must select –1 before you type the comma.

A prefix function is one that is typed before its arguments. To enter a prefix function, you can:

•type the first argument, select it, then select the function from a menu, or

•you can select the function from a menu, or by directly entering it in Alpha mode, and then type the arguments.

The following example illustrates the various ways of entering a prefix function. Suppose you want to factor the expression x2 – 4, then find its value for x = 4. FACTOR is the function for factoring, and it is found on the menu. SUBST is the function for substituting a value for a variable in an expression, and it is also found in the menu.

l

Equation Writer

15-13