>>236
It's genuinely a false statement, it should read infinity. Negative one over 12 comes from the Riemann Zeta function, which can be evaluated using the above formula for values where it converges. To define it for values where it doesn't converge, they used different equations that agree for those values but have a larger domain. These larger domain equations are where the negative one over 12 comes from.
https://en.wikipedia.org/wiki/Analytic_continuation