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

By C. C. Edwards

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 + bi, and


The last two options are used when working with complex numbers. The a + bi 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 + bi 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 + bi 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][.].)