HP 15c - Manual (Page 133)

Section 11: Calculating With Complex Numbers 133
Complex Results from Real Numbers
In the preceding examples, the entry of complex numbers had ensured the
(automatic) activation of Complex mode. There will be times, however,
when you will need Complex mode to perform certain operations on real
numbers, such as
5

. (Without Complex mode, such as operation would
result in an Error 0 – improper math function.) To activate Complex mode
at any time and without disturbing the stack contents, set flag 8 before
executing the function in question.
*
Example: The arc sine (sin
-1
) of 2.404 normally would result in an Error 0 .
Assuming 2.404 in the X-register, the complex value arc sin 2.404 can be
calculated as follows:
Keystrokes Display
| F 8
Activates Complex Mode.
| , 1.5708
Real part of
arc sin 2.404.
´ % (hold) -1.5239
Imaginary part of
arc sin 2.404.
(release)
1.5708
Display shows real part
again when % is
released.
Polar and Rectangular Coordinate Conversions
In many applications, complex numbers are represented in polar form,
sometimes using phasor notation. However, the HP-15C assumes that any
complex numbers are in rectangular form. Therefore, any numbers in polar
or phasor form must be converted to rectangular form before performing a
function in Complex mode.
* Pressing ´ } twice will accomplish the same thing. The sequence ´ V is not used because
it would combine any numbers, in the real X-. and Y-registers into a single complex number.