Complex Roots On The Hp 40Gs - HP 39gs Master Manual

C o m p l e x R o o t s
C o m p l e x R o o t s
i. Find all roots of the complex polynomial f z
ii. Find the complex roots of z
On the hp 40gs you can obtain exact roots for polynomials using the
CAS function
SOLVEVX
CAS is in its default configuration. See page 324 for more details on
the CAS.
In the view, press the
HOME
button to access the Solve menu. Scroll down to find
and press .
ENTER
Type in the function using the default variable
highlight the entire expression. The result should be as shown right.
If you press at this moment then the result will probably be
ENTER
" " because we need to set one of the configuration
NO_SOLUTION
flags. Press
SHIFT MODES
right.
In the configuration screen, move the highlight to the "Num. factor"
option shown right and press
from the configuration menu and return to the main screen.
Now press to tell the calculator to execute the
ENTER
command. The calculator will then ask if you want to turn "Complex
Mode" on. Tell it
will allow you to scroll right and left through the solutions.
VIEWS
A similar result can be found for the second equation. The calculator will
ask you if you want to turn "Approximation mode" on. If you respond
with then the result will be as shown right. Responding with
instead will result in the second screen below right. Note that "Approx
mode" will be left active and you should choose "Exact mode" through
the configuration menu if you don't want decimal results from that point
on.
An alternative to using the
difference will be that the results will be in factor form rather than roots.
o n t h e h p 4 0 g s
o n t h e h p 4 0 g s
= 32 .
5
. The instructions following assume that the
button to enter the CAS. Press the
X
to enter the configuration menu shown
to set it. Then press
. The final result is shown right. Pressing
function is to use
SOLVEVX
( ) = z + iz − 4z − 4
3 2
SOLVEVX
rather than and then
Z
to quit
SOLVEVX
. The
FACTOR
309
i .