3 ms·* i = sqrt(-1) * i * i = i^2 = sqrt(-1) * sqrt(-1) = -1 .. i^4 = i^2 * i^2 = -1 * -1 = 1by irishcoffee 14y ago* i = sqrt(-1) * i * i = i^2 = sqrt(-1) * sqrt(-1) = -1 .. i^4 = i^2 * i^2 = -1 * -1 = 1