Weil Conjectures. Let $V/\mathbb{F}_q$ be a smooth projective variety of dimension $N$.
(b) Functional Equation. There is an integer $\epsilon$, called the Euler characteristic of $V$, such that$$Z(V/\mathbb{F}_q; 1/q^NT) = \pm q^{N\epsilon/2}T^\epsilon Z(V/\mathbb{F}_q; T).$$
Question. Let $V/\mathbb{F}_q$ be a smooth projective variety of dimension $N$ defined over a finite field, and let $\epsilon$ be the Euler characteristic of $V$, as described above. How do I see that up to $\pm1$, the function$$q^{-\epsilon s/2} Z(V/\mathbb{F}_q; q^{-s})$$is invariant under the substitution $s \mapsto N - s$?