Texas Instruments TI-89 Titanium User Manual page 583

If a program has local variables, a graphed function cannot access them. For
Note:
example:
Local a
5!a
Graph aùcos(x)
may display an error or an unexpected result (if
folder).
Circular Definition Errors
When evaluating a user-defined function or running a program, you can specify an
argument that includes the same variable that was used to define the function or create
the program. However, to avoid Circular definition errors, you must assign a value for
x or i variables that are used in evaluating the function or running the program.
For example:
Ê
x+1!x
– or –
For i,i,10,1
Ê
Disp i
EndFor
Ê
Causes a Circular definition error message if x or i does not have a value. The error
does not occur if x or i has already been assigned a value.
Programming
is an existing variable in the current
a
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