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2005 AMC 12B Question 22

AMC12 · 2005 AMC 12B

Question 22

A sequence of complex numbers $z_0,$ $z_1,$ $z_2,$ $\ldots$ is defined by the rule $$
z_{n+1} = \dfrac{i z_n}{\overline{z_n}},
$$ where $\overline{z_n}$ is the complex conjugate of $z_n$ and $i^2 = -1.$ Suppose that $|z_0| = 1$ and $z_{2005} = 1.$ How many possible values are there for $z_0?$
  1. $1$
  2. $2$
  3. $4$
  4. $2005$
  5. $2^{2005}$