Defining Functions In The Y= List - Texas Instruments TI-80 Manual Book

Defining Functions in the Y= List

Pressing ( displays the Y= edit screen. This is where you enter the functions to
graph. You can store up to four functions in memory at one time. You can graph
one or more of these functions at a time.
Displaying the
Functions in the
Y= List
Defining a New
Function
Press ( to display the
the Y1 and Y2 functions are defined.
To define a new function in the
1. Press ( to display the
2. Move the cursor to the function in the
define. If necessary, press M to erase a previously
entered function.
3. Enter the expression to define the function.
¦
You may use functions and variables in the expression.
If the expression evaluates to a value that is not a real
number, that point is not plotted; an error does not
occur.
¦
The independent variable in the function is
press @, rather than pressing ? ã
variable. (
FUNC
as .)
X
¦
The expression is stored as one of the four user-defined
functions in the
Note: You can use a list within a
the function must evaluate to a single value.
4. When you complete the expression, press ¸ to move
to the beginning of the next function.
Note: When you enter a function, it is automatically selected
for graphing in the
equal sign. For details on selecting and deselecting functions,
see page 4-8.
Y= edit screen. In the example below,
Y= list:
edit screen.
Y=
mode defines the independent variable
Y= list as you enter it.
Y= list. This is indicated by the highlighted
Function Graphing 4-5
Y= list you want to
. You may
X
ä, to enter the
X
Y= function; however,
X