Datasheet

308
P
P
i
i
e
e
c
c
e
e
w
w
i
i
s
s
e
e
D
D
e
e
f
f
i
i
n
n
e
e
d
d
F
F
u
u
n
n
c
c
t
t
i
i
o
o
n
n
s
s
Piecewise defined functions can be graphed easily on the hp 39g+ by
breaking them up into their components.
For example:
()
()
()
2
sin ; 2
2;21
21 ; 1
xx
fx x x
xx

<−


=+ −≤≤


−− >


Using the Function aplet, we enter three separate component functions. You
can obtain the inequality signs from the CHARS menu.
F1(X)=SIN(X)/(X<-2)
F2(X)=(X+2)/(-2≤X AND X≤1)
F3(X)=((X-2)
2
-1)/(X>1)
The calculator evaluates the domain as either true (1) or false (0) for each
value of x. When it is zero (outside the domain) then dividing by this value
causes the function to become undefined and consequently not be graphed.
Inside the domain it has no effect.
Note: The word ‘AND’ is available from the keyboard above the (-) sign.
S
S
e
e
q
q
u
u
e
e
n
n
c
c
e
e
s
s
a
a
n
n
d
d
S
S
e
e
r
r
i
i
e
e
s
s
Through the Sequence aplet the hp 39g+ provides very flexible tools for the
investigation of sequences. These can easily be adapted to investigate
series as well.
Information and worked examples of using the hp 39g+ for evaluation of
sequences and series can be found in the chapter “Tips & Tricks -
Sequences and Series” on page 110.
Note: One of the common errors that students make in the Solve aplet is to
try to solve for solutions which do not exist. For example, a student will try to
solve for N in T=A*R^(N-1) with A=50, R=0.75 and T= -2. The result will be
firstly that the calculator will seem to freeze while it tries to find a solution
which can only be approached asymptotically.