1 − 2 + 3 − 4 + ⋯
In mathematics, 1 − 2 + 3 − 4 + ··· is an infinite series whose terms are the successive positive integers, given alternating signs. In 1891, Ernesto Cesàro expressed hope that divergent series would be rigorously brought into calculus, pointing out that both the sides are equal to 1⁄4.
