What is equivalent to the complex number i to the power of 21?

Answer 1

I use the ^ symbol to mean 'to the power of' and * to mean multiply. You want to find i^21

Remember i^4 = i^2 * i^2 = -1 * -1 = 1

So i^21 = i^4 * i^4 * i^4 * i^4 * i^4 * i^1 = 1 * 1 * 1 * 1 * 1 * i = i.

Answer 2

Just multiply "i" by itself, 21 times. Note that for every 4 factors of "i", you get a "1" - so you can separate "i to the power 21" as "i to the power 20" times "i".