The Real Command

Command Summary

Enables real number only mode.

Command Syntax

Real

While editing a program, press:

1. MODE to access the mode menu.
2. Use arrows and ENTER to select Real.

TI-83/84/+/SE

1 byte

The Real command puts the calculator in real number-only mode. This shouldn't be taken quite literally, as you can still type in i to get complex numbers, and do operations with them (they will be displayed as in a+bi mode, in that case). However, any operation done with real numbers that comes out to a complex result, such as taking the square root of a negative number, will throw a ERR:NONREAL ANS error.

There is no real advantage to using Real mode over a+bi mode — it just adds another error condition that wouldn't be triggered otherwise. However, it is the default setting, and so there's a good chance that the calculator will be in Real mode when someone runs your program. Thus, when using complex numbers implicitly (such as in a quadratic equation solver) you should do something about this.

Rather than switch to a+bi mode, you might want to force the calculations to use complex numbers by making the original argument complex. The general way to do this is by adding +0i to the number. However, there may be an optimization in any particular case. See the quadratic formula routine for a good example of this.

``````Real
Done
√(-1)
(causes an error)
√(-1+0i)
i```
```