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Questions about security products, product marketing, what to avoid doing with a five-inch quad, or how to revive a dead LiPo without blowing it up. All welcome.

Show that ∑(n=1→∞) arctan( 1 ÷ (n² + n + 1) ) = π/4

Answer below. Stuck? There is a hint.

Just kidding, here’s the actual question:

What is four plus six?

A quick check that you are human. Digits or words both work.