HP 15c User Manual

Page 122

122 Section 11: Calculating With Complex Numbers

Example: Add 2 + 3i and 4 + 5i. (The operations are illustrated in the stack
diagrams following the keystroke listing.)

Keystrokes

Display

´ • 4

2.0000

Keys real part of first number
into (real) Y-register.

Keys imaginary part of first
number into (real)
X-register.

´ V

2.0000

Creates imaginary stack; moves
the 3 into the imaginary X-
register, and drops the 2 into the
real X-register.

4.0000

Keys real part of second number
into (real) Y-register.

Keys imaginary part of second
number into (real) X-register.

´ V

4.0000

Copies 5 from real
X-register into imaginary
X-register, copies 4 from real Y-
register into real X-register, and
drops stack.

6.0000

Real part of sum.

´ % (hold)

8.0000

Displays imaginary part

(release)

6.0000

of sum while the % key is held.
(This also terminates digit entry.)

The operation of the real and imaginary stacks during this process is
illustrated below. (Assume that the stack registers have been loaded already
with the numbers shown as the result of previous calculations). Note that
the imaginary stack, which is shown below at the right of the real stack, is
not created until ´ V is pressed. (Recall also that the shading of the
stack indicates that those contents will be written over when the next
number is keyed in or recalled.)