HP 15c - Manual (Page 72)

72 Section 3: Calculating in Complex Mode
72
Keystrokes Display
8 054- 8
® 055- 34
÷ 056- 10
+ 057- 40
|a 058- 43 16 Calculates |e
z
+ 8/(z + 9)|.
|n 059- 43 32
Labels used: A, B, and C.
Registers used: R
0
and R
1
.
Now run the program. For each root, press B until the displayed real part doesn't change.
(You might also check that the imaginary part doesn't change.)
Keystrokes Display
|¥
Run mode.
´U Activates User mode.
0
A 1.6279 Displays Re(A(0)) = Re(z
0
).
B -0.1487 Re(z
1
).
B -0.1497 Re(z
2
).
B -0.1497 Re(z).
´% (hold) 2.8319 Im(z).
C 1.0000 -10 Calculates residual.
® -0.1497 Restores z to X-register.
By repeating the same process for n = 1 through 5, you will obtain the results listed below.
(Only one of each pair of complex roots is listed.)
n A(n) Root z
k
Residual
0 1.6279 + i1.5708 -0.1497 + i2.8319 1 × 10
−10
1 0.0184 + i7.8540 - 0.4198 + i 8.6361 6 × 10
−10
2 -0.5694 + i14.1372 -0.7430 + i14.6504 2 × 10
−9
3 -0.9371 + i20.4204 -1.0236 + i20.7868 5 × 10
−10
4 -1.2054 + i26.7035 -1.2553 + i26.9830 9 × 10
−10
5 -1.1467 + i32.9867 -1.4486 + i33.2103 2 × 10
−9
As n increases, the first guess A(n) comes ever closer to the desired root z. (When you're
finished, press ´U to deactivate User mode.)