Talk:Simplify powers of the imaginary unit/@comment-25304012-20150422204529/@comment-25768713-20150727071355

i = sqrt(-1)

i^2 = -1 because sqrt(-1) * sqrt(-1) = -1 cuz the rad sign cancels

i^3 = -i because i * i^2 = i^3 and i * -1 is -i

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