Owner's Manual

Appendix B: Technical Reference 934
Regardless of the Complex Format mode setting, variables that have no
stored value and that do not end with an underscore (_) are treated as real
numbers. To perform complex symbolic analysis, you can use either of the
following methods to set up a complex variable.
Method 1: Use an underscore _
(TI.89 Titanium:
¥  Voyage™ 200 2 ) as the last character in the
variable name to designate a complex variable. For example:
z_ is treated as a
complex variable if it does
not have a stored value.
Method 2: Store an unreal value into any variable. For example:
x+y i
ii
i !z
Then z is treated as a
complex variable.
Radian angle mode is recommended for complex number calculations.
Internally, the TI-89 Titanium / Voyage™ 200 converts all entered trig values
to radians, but it does not convert values for exponential, logarithmic, or
hyperbolic functions.
In Degree and Gradian angle modes, complex identities such as e^(
i
ii
i q) =
cos(q) +
i
ii
i sin(q) are not generally true because the values for cos and sin
are converted to radians, while those for e^(
) are not. For example, e^( i
ii
i 45)
= cos(45) +
i
ii
i sin(45) is treated internally as e^( i
ii
i 45) = cos(p/4) + i
ii
i sin(p/4).
Complex identities are always true in Radian angle mode.
Using Complex
Variables in
Symbolic
Calculations
Note: For best results in
calculations such as
cSolve() and cZeros(), use
Method 1.
Complex Numbers
and Degree Mode
Note: If you use Degree or
Gradian angle mode, you
must make polar entries in
the form (r
q ). In Degree or
Gradian angle mode, an r
e
i
ii
i
q
entry causes an error.