In order to find the maximum or minimum values of a function, a graph must already be displayed on the screen. To learn how to enter and graph a function, go to Graphing a Function. Consider the function, = , which is graphed below
A relative maximum point is a point where the graph reaches a peak. To find the relative maximum point press 2nd TRACE [CALC], then select 4:Maximum.
Use the Left Arrow Key to move the flashing cursor slightly to the left of the maximum point and then press ENTER.
The left bound is now marked with a small arrow above the graph.
Now use the Right Arrow Key to move the flashing cursor slightly to the right of the maximum point and then press ENTER.
Note that both the left bound and right bound are now marked with a small arrows above the graph.
Move the curser as close to the maximum point as possible, and press ENTER again. The last screen shows that the relative maximum point is about (-1.29, 5.30). Thus, the maximum value of the function is approximately 5.30 (the y coordinate of the maximum point).
A relative minimum point is a point where the graph dips into a valley. To find the relative minimum point, repeat the above process, except select 3:Minimum instead of 4:Maximum.