HP 40gs HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010.p - Page 352

Example 9: Investigation of a complex function, in parametric form and graph it. Show

Page 352 highlights

Example 9: Investigation of a complex function ( ) Rewrite the function f z = 1 z2 + z in parametric form and graph it. Show 2 that it is symmetrical about the x axis and evaluate f ⎛ ⎜⎝ π 3 ⎞ ⎟ ⎠ as an exact surd. i. The first step is to enter the function. 1 2 ALPHA Z ALPHA Z ii. We now transform it into exponential form by using the SUBST function to replace z with ei⋅t . SHIFT ENTER e ALPHA Z SHIFT = SHIFT x SHIFT i SHIFT ALPHA t SHIFT ENTER Note: The reason for pressing within the menu is to jump to the first function starting with an S, the letter on the key. Pressing it again jumps to the next function starting with S, which is SUBST. iii. Next we linearize it... ENTER ENTER ENTER Note: 1. As in the previous case, the is used to jump to the first function that starts with an L, the letter on . 2. The hp 40gs will probably ask if it should turn "Complex mode" on, assuming it is in its default configuration. One of the ENTERs is to tell it "Yes". 352

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Example 9: Investigation of a complex function
()
=
1
z
2
+
z
in parametric form and graph it. Show
Rewrite the function
f
z
2
π
that it is symmetrical about the x axis and evaluate
f
as an exact surd.
3
i.
The first step is to enter the function.
1
2
ALPHA Z
ALPHA Z
ii.
We now transform it into exponential form by using the
SUBST
function to replace z with
e
it
.
SHIFT
ENTER
ALPHA Z SHIFT = SHIFT
e
x
SHIFT i SHIFT
ALPHA t
SHIFT
ENTER
Note:
The reason for pressing
within the menu
is to jump to the first function starting with an
S
, the letter on the
key.
Pressing it again jumps to the next function starting
with
S
, which is
SUBST
.
iii.
Next we linearize it…
ENTER ENTER
ENTER
Note:
1. As in the previous case, the
is used
to jump to the first function that starts with
an
L
, the letter on
.
2. The hp 40gs will probably ask if it should
turn “Complex mode” on, assuming it is in
its default configuration. One of the
ENTER
s
is to tell it “Yes”.
352