Texas Instruments TI-89 Titanium User Manual page 234

Default Simplification Rules
All of the following rules are applied automatically. You do not see intermediate results.
• If a variable has a defined value, that
value replaces the variable.
If the variable is defined in terms of
another variable, the variable is replaced
with its "lowest level" value (called infinite
lookup).
Default simplification does not modify variables that use path names to indicate a
folder. For example, x+class\x does not simplify to 2x.
For information about folders, refer to the Calculator Home Screen module.
Note:
• For functions:
- The arguments are simplified. (Some built-in functions delay simplification of
some of their arguments.)
- If the function is a built-in or user-defined function, the function definition is
applied to the simplified arguments. Then the functional form is replaced with
this result.
• Numeric subexpressions are combined.
• Products and sums are sorted into order.
Symbolic Manipulation 231