$\displaystyle\zeta(2) =\frac{\pi^2}{6}!$

Calculus Level 3

Given that

$\sum_{r=1}^{\infty} \frac{1}{r^2} = \frac{ \pi^2} { 6},$

Evaluate the sum

$\displaystyle\sum_{r=0}^{\infty}\frac{1}{(2r+1)^2}.$

Note: Do NOT use WolframAlpha.