Texas Instruments TI-84 PLUS - Graphing Calculator Manual Book page 58

On the TI-84 Plus, complex numbers can be stored to variables. Also, complex numbers are valid
list elements.
In Real mode, complex-number results return an error, unless you entered a complex number as
input. For example, in Real mode returns an error; in mode returns an answer.
ln( 1) a+bi ln( 1)
L L
Real mode mode
a+bi
$ $
Entering Complex Numbers
Complex numbers are stored in rectangular form, but you can enter a complex number in
rectangular form or polar form, regardless of the mode setting. The components of complex
numbers can be real numbers or expressions that evaluate to real numbers; expressions are
evaluated when the command is executed.
You can enter fractions in complex numbers, but the output will always be a decimal value.
When you use the n/d template, a fraction cannot contain a complex number.
"
You can use division to compute the answer:
Chapter 2: Math, Angle, and Test Operations 51