Question

Which is equivalent to i224?

Answer 1

When i is raised to some positive integer exponent, there are only four possibilities.

First, divide said exponent by 4.

Is there no remainder? Then the answer is 1.
Is there a remainder of 1? Then the answer is i.
Is there a remainder of 2? Then the answer is -1.
Is there a remainder of 3? Then the answer is -i.

Cheers :)

Answer 2

i^n has four possible values, depending upon n, as stated above. If you're given i^224 (note that the 224 is a power, not a multiplier), try dividing that power, 224, by 4. Is there a remainder or not? Follow terenzreignz' advice from that point on.