For a positive integer n, find the value of (1−i)n(1−1i)n.
(1−i)n(1−1i)n=(1−i)n(i−1i)={(1−i)(i−1)i}n={(1−i)(1−i)−i}n={(1−i)2−i}n={1−2i−1−i}n={−2i−i}n=2n