Complex Numbers on the TI-83

Note that the TI-83 and the TI-83 plus have slightly different keys. This page uses the keys associated with the TI-83. The differences are that the TI-83 key is replaced by the TI-83 Plus key, and the TI-83 key is replaced by the TI-83 Plus key.

In Chapter 1, section 1, the textbook gives some examples of doing complex number arithmetic on a TI-86. That calculator uses the symbol (4,2) to represent 4+2i. The TI-83, however, uses the i symbol to indicate a complex number. That symbol is found above the key. The following screens demonstrate doing examples 8 through 11 on the TI-83

Figure 1

The keystrokes to generate Example 8, (2 + 3i) + (– 5 + i) are . The result is – 3+4i. The keystrokes for Example 9 are . The result is 5. The keystrokes for Example 10 are . The result is 12+i.

Figure 2

For Example 10 we could try . The result is .3+1.1i. If we want to express each of the components of the complex number as fractions. then we could recall the previous command via, , followed by moving to the MATH menu via , and selecting option 1, via , which will formulate the last command in Figure 2. Then we press to process the expression and to produce (3/10)+(11/10)i. Note that we just included parentheses to make it absolutely clear that the i is not in the denominator.