A-Best: i = sqrt (-1)
i^2 = -1
i^3 = -i
i^4 = 1
Divide 82 by 4 and you get 20, remainder 2.
Take the expression of i to the power of two (i^2), whichis equal to -1.
A: Kind of do it like a pattern. If i = square root of -1, then i^2 is -1, i^3 is -(square root of -1) and i^4 is 1. Keep this going, but really, every 4th power brings you back to 1. 82 is 20 times 4 plus 2, so just concentrate on the 2. i^2 is -1, so 1x1x1x1x1x1x1x1x1x1x1x1x1x1x1x1x1x1x1x1x(-1) = -1.
