Powers of i

*i^1=i i^2= -1 i^3=-i i^4=1

To find what i to a different power is, however, you take the number that i is to the power to and divide that number by four. Whatever the remainder is is your new power of i then based on the four powers you know, you can solve from there. So let's say you have i^22... You would divide 15 by 4 and get 5 with a remainder of 2 (5 R 2). Next you would take i^2 and your answer would be -1.

*^ means square the number before the ^ by the number after