Texas Instruments Titanium TI-89, User Manual

Page: 749 / 977

Activities 746
2. Copy and paste the last answer to the
entry line and store it in the function
f(x)
.
Note:
Move the cursor into the history
area to highlight the last answer and
press
¸
, to copy it to the entry line.
3. Use the
abs( )
function to find the absolute
value of
f(x+y i )
.
(This calculation may take about 2
minutes.)
Note:
The absolute value of a function
forces any roots to visually just touch
rather than cross the
x
axis. Likewise, the
absolute value of a function of two
variables will force any roots to visually
just touch the
xy
plane.
4. Copy and paste the last answer to the
entry line and store it in the function
z1(x,y)
.
Note:
The graph of
z1(x,y)
will be the
modulus surface.