3-10 Function aplet
FCN functions The FCN functions are:
Function Description 
Root Select Root to find the root of the 
current function nearest the 
cursor. If no root is found, but only 
an extremum, then the result is 
labeled EXTR: instead of ROOT:. 
(The root-finder is also used in the 
Solve aplet. See also “Interpreting 
results” on page 7-6.) The cursor 
is moved to the root value on the 
x-axis and the resulting x-value is 
saved in a variable named 
ROOT. 
Extremum Select Extremum to find the 
maximum or minimum of the 
current function nearest the 
cursor. This displays the 
coordinate values and moves the 
cursor to the extremum. The 
resulting value is saved in a 
variable named EXTREMUM.
Slope Select Slope to find the numeric 
derivative at the current position 
of the cursor. The result is saved in 
a variable named SLOPE. 
Signed area Select Signed area to find the 
numeric integral. (If there are two 
or more expressions 
checkmarked, then you will be 
asked to choose the second 
expression from a list that 
includes the x-axis.) Select a 
starting point, then move the 
cursor to selection ending point. 
The result is saved in a variable 
named AREA. 
HP 39gs English.book  Page 10  Wednesday, December 7, 2005  11:24 PM