Texas Instruments TI-83 Manual Book page 562

Ë , and then press Í to enter
Or, press
3 8
a guess for the maximum.
When you press a number key in , the
X=
TRACE
prompt is displayed in the bottom-left corner.
Notice how the values for the calculated
maximum compare with the maximums found
with the free-moving cursor, the trace cursor,
and the table.
Note: In steps 2 and 3 above, you can enter values
directly for Left Bound and Right Bound, in the same
way as described in step 4.
TI-83 Plus Activities 559