# Set the Mode and Use Complex Numbers on TI-83 Plus

On the TI-83 Plus graphing calculator, you can set the mode and use complex numbers. The second from the last line of the Mode menu gives you three options: **Real**, **a + b**** i**, and

The last two options are used when working with complex numbers. The **a + b**** i** options tells the calculator to display complex numbers in rectangular form, and the

options tells it to display complex numbers in polar form.

Select either **a + b**** i** or

so the calculator knows you’re working with complex numbers. The remaining menu items can be set as they appear in the figure.

Independent of the mode setting, **a + b***i** *or

complex numbers can be entered in the calculator in either *a* + *bi* rectangular form or in

polar form. You enter the imaginary number *i *in an expression by pressing **[2nd][.]**; *e* is entered by pressing

If the calculator is in Radian mode,

in the polar form of a complex number is entered in radian measure; if the calculator is in Degree mode,

is entered in degrees.

Although the figures in these examples involve real-number arithmetic, everything can be used when doing complex-number arithmetic — provided the calculator is in Complex mode. (Remember, you can enter the imaginary number *i *into an expression by pressing **[2nd][.]**.)