Evaluate the value of [(-1 + √-3)/2]¹⁰⁰ + [(-1 - √-3)/2]¹⁰⁰.
2
0
-1
1
Correct answer: -1
Solution
(-1 +/- sqrt(-3))/2 are the complex cube roots of unity omega and omega^2. Since 100 ≡ 1 and 200 ≡ 2 (mod 3), the sum is omega^100 + (omega^2)^100 = omega + omega^2 = -1.