Texas Instruments TITANIUM TI-89 - Manual (Page 248)

Symbolic Manipulation 248
Note: You may or may not want to define a numeric value for var , depending on the
situation.
For example:
Note: The example to the right finds the derivative
of x
3
at x=5. If x
3
was initially simplified to 75, you
would find the derivative of 75, which is not what
you want.
x cannot be simplified.
x is not simplified. The function uses x
3
,
and then substitutes 5 for x.
x is simplified to t. The function uses t
3
.
x is simplified to t. The function uses t
3
,
and then substitutes 5 for t.