You can define
functions on the calculator with the STO command
or with the Define command.
(The Define
command is on the F4, Other menu.)
Functions
can take any number of variables as inputs.
You don't
need to use the same variable(s) when you call up the function as when
you define it.
Functions
with single-letter names disappear when you invoke NewProb
or F6,1.
Functions
with multi-letter names disappear when you use delvar to delete
them. Delvar is on the Other menu.
If you're
defining a function just so you can look at its graph,
y1(x) is a good name; it automatically puts the formula on the Y=
screen.
You can
also define functions, including multi-line definitions, using the Program
Editor from the APPS menu. See your owner's manual
for details.