posted by kate .
let i = the square root of -1 with i to the 1st power =i, i to the 2nd power= -1, i to the 3rd power =-i , i to the 4th power=1 find ito the power 215
i^215 = i^212*i^3 = i^3 = -i
(i^212 = 1 because 212 is evenly divisible by 4)
In other words,
i^212 = (i^4)^53 = 1^53 = 1