Powers of i

What this lesson shows

i is the number whose square is minus 1. Raise it to higher and higher powers and something surprising happens — it starts going round in circles.

Try it yourself

Real questions from this lesson's worksheets — answers below each one.

1. Simplify i¹
   Show answer

   i
2. True or false: i² = -1
   Show answer

   True
3. Which of these equals 1?
   Show answer

   i⁴
4. Simplify i² × i²
   Show answer

   1