Question

Simplify. i23
A. 1
B. -1
C. -i
D. i

Answer 1

\[i^{23} = -i\]

Answer 2

take the integer remainder when you divide 23 by 4
since 4 goes in to 20 evenly, the remainder is 3
so
\[i^{23}=i^3=-i\]