The minimum of a function is found by using the extremum option.
While viewing a graph, press 
to view the math menu.
Move the cursor near the desired point of minimum and
press 
to select the extremum option.
The coordinates of the minimum point appear at the bottom of the screen
and are added to the stack.
Here, the point is about (2.171 , -1).
Note: If there is more than one function the HP will find minimum points
only on the first function. To rotate through functions select
Next Equation by pressing 
in the math menu.
The first equation will be put at the end of the list and all others move
up one spot.