Tap the blue circles to see an explanation.
| $$ \begin{aligned}i^{20}i^3& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}i^{23} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-i\end{aligned} $$ | |
| ① | $$ i^{20} i^3 = i^{20 + 3} = i^{23} $$ |
| ② | $$ i^{23} = i^{4 \cdot 5 + 3} =
\left( i^4 \right)^{ 5 } \cdot i^3 =
1^{ 5 } \cdot (-i) =
-i = -i $$ |