Problems, their history and their proofs.https://bmscomp.github.io/https://bmscomp.github.io/mathematics/basel-problem/https://bmscomp.github.io/mathematics/basel-problem/For almost ninety years nobody could say what 1 + 1/4 + 1/9 + ⋯ adds up to. How Euler found the answer, π²/6, how he proved it, and three later proofs that each find the π somewhere else.Wed, 30 Sep 2026 00:00:00 GMTmathematicsserieshistory