In header: $\sum_{k=1}^{\infty} \sfrac{1}{k^2} = \sfrac{\pi^2}{6}$

In header: $\sum_{k=1}^{\infty} \sfrac{1}{k^2} = \sfrac{\pi^2}{6}$

In header: $\sum_{k=1}^{\infty} \sfrac{1}{k^2} = \sfrac{\pi^2}{6}$

In header: $\sum_{k=1}^{\infty} \sfrac{1}{k^2} = \sfrac{\pi^2}{6}$

In header: $\sum_{k=1}^{\infty} \sfrac{1}{k^2} = \sfrac{\pi^2}{6}$

In header: $\sum_{k=1}^{\infty} \sfrac{1}{k^2} = \sfrac{\pi^2}{6}$