Symbolic Calculations - Texas Instruments TI-89 Titanium User Manual

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
angle mode, you must make
polar entries in the form
(r q ). In Degree angle
i q
mode, an r e entry causes
an error.
Appendix B: Technical Reference
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: ¥
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+yi!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 angle mode, complex identities such as e ^(iq) = cos(q) + 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 45 ) = cos(45) +
i sin(45) is treated internally as e ^(i45) = cos(p/4) + i sin(p/4). Complex
identities are always true in Radian angle mode.
2
Voyage™ 200 ) as the last character in
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