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2008 AMC 12B Question 19

AMC12 · 2008 AMC 12B

Question 19

A function $f$ is defined by $f(z) = (4 + i)z^2 + \alpha z + \gamma$ for all complex numbers $z,$ where $\alpha$ and $\gamma$ are complex numbers and $i^2 = -1.$ Suppose that $f(1)$ and $f(i)$ are both real. What is the smallest possible value of $|\alpha| + |\gamma|?$
  1. $1$
  2. $\sqrt{2}$
  3. $2$
  4. $2\sqrt{2}$
  5. $4$