Other Content

Note (CAS): Functions and programs cannot use a local variable to perform
symbolic calculations.
CAS: Performing Symbolic Calculations
If you want a function or program to perform symbolic calculations, you must
use a global variable instead of a local. However, you must be certain that the
global variable does not already exist outside of the program. The following
methods can help.
• Refer to a global variable name, typically with two or more characters, that
is not likely to exist outside of the function or program.
• Include DelVar within a program to delete the global variable, if it exists,
before referring to it. (DelVar does not delete locked or linked variables.)
Differences Between Functions and Programs
A function defined in the Program Editor is similar to the functions built into the
TI-Nspire™ Software.
• Functions must return a result, which can be graphed or entered in a table.
Programs do not return a result.
• You can use a function (but not a program) within an expression. For
example: 3 ¦ func1(3) is valid, but not 3 ¦ prog1(3).
• You can run programs from Calculator and Notes applications only.
However, you can evaluate functions in Calculator, Notes, Lists &
Spreadsheet, Graphs & Geometry, and Data & Statistics.
• A function can refer to any variable; however, it can store a value to a local
variable only. Programs can store to local and global variables.
Note: Arguments used to pass values to a function are treated as local
variables automatically. If you want to store to any other variables, you
must declare them as Local from within the function.
• A function cannot call a program as a subroutine, but it can call another
user-defined function.
• You cannot define a program within a function.
• A function cannot define a global function, but it can define a local function.
Getting Started with the Program Editor 499