HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010

The advantage of doing it this way is that if you zoom in or out by a factor of 2 or 4 or 5, the cursor jumps
will stay at (relatively) nice values allowing you to trace more easily. In this case, the cursor now moves in
jumps of 0
.
05, which is ideal for most purposes. If you are not interested in tracing along the graph then this
may not be important.
The disadvantage of this method is that you need to have at least some of the graph showing on the screen
before you can zoom in or out to show more! Auto Scale can sometimes give you this first step.
Composite functions
The Function aplet is capable of dealing with composite functions such as
fx
+
2
)
or fgx in its SYMB
view. The
(
(
()
)
and keys are particularly helpful with this.
x , then we can use these in our defining of F3(X),
F4(X). See the screen shot on the left below.
1( ) =
For example, if we define
Fx x
2
−1
and
F
2( x) =
If the highlight is now positioned on each of these in turn, and the
key pressed then the substitution is
performed. The result is shown in the right hand snapshot.
x
−
2
Notice that the calculator is smart enough to realize in
F3(X) that
(
)
1 is the same as x −1 , although
not, unfortunately, smart enough to keep track of the implications for the domain, which are that
F3(X) should
be defined only for non-negative x.
There is a limit to this however. If you define
Fx x x 11( )
=
2
−− and then
2( ) = 1( Fx Fx +1) , then the routine will not simplify
2
(
x 1
)
x
(
x +1
)
− + −1 to x
2
+−1 .
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