Riemann zeta special values

(1)   \begin{equation*}\zeta(2)=\frac{\pi^2}{6}\end{equation*}

(2)   \begin{equation*}\zeta(4)=\frac{\pi^4}{90}\end{equation*}

(3)   \begin{equation*}\zeta(6)=\frac{\pi^6}{945}\end{equation*}