How does 1+2+3+4+5+6...equal to -1/12.
Yes, this is true in complex analysis of Riemann zeta function, when zeta = -1. It involves the most advanced Math, including using Complex numbers.
The great Indian mathematician S. Ramanujan discovered it independently at the turn of this last century and attempted to prove it using an infinite series. You can read about his attempt to do so here: https://en.wikipedia.org/wiki/1_%2B_2_%2B_3_%2B_4_%2B_%E2%8B%AF
