If ((1+i)/(1-i))^x = 1, then
- A. x = 2n + 1, where n is any positive integer
- B. x = 2n, where n is any positive integer
- C. x = 4n + 1, where n is any positive integer
- D. x = 4n, where n is any positive integer
Answer: D. x = 4n, where n is any positive integer
Explanation: (1+i)/(1-i) = (1+i)² / 2 = 2i/2 = i. The equation becomes i^x = 1. Since i⁴ = 1, i^x = 1 is satisfied when x is a multiple of 4, i.e., x = 4n for any positive integer n.