HP HP-15C

132 Section 11: Calculating With Complex Numbers
Conditional Tests
For programming, the four conditional tests below will work in the complex
sense: ~ and T 0 compare the complex number in the (real and
imaginary) X-registers to 0 + 0i, while T 5 and T 6 compare the
complex numbers in the (real and imaginary) X- and Y-registers. All other
conditional tests besides those listed below ignore the imaginary stack.
~ T 0  T 5 (x = y) T 6 
Example: Complex Arithmetic. The characteristic impedance of a ladder
network is given by an equation of the form
B
A
Z 
0
,
where A and B are complex numbers. Find Z
0
for the hypothetical values
A = 1.2 + 4.7i and B = 2.7 + 3.2i.
Keystrokes
Display
1.2 v 4.7 ´ V
1.2000
Enters A into real and
imaginary X-registers.
2.7 v 3.2 ´ V
2.7000
Enters B into real and
imaginary X-registers,
moving A into real and
imaginary Y-registers.
÷
1.0428
Calculates A/B.
¤
1.0491
Calculates Z
0
and
displays real part.
´ % (hold)
0.2406
Displays imaginary part
of Z
0
while % is held
down.
(release)
1.0491
Again displays real part
of Z
0
.