Question Number 102686 by Dwaipayan Shikari last updated on 10/Jul/20

Σ_(r=1) ^∞ i^r +Σ_(r=0) ^∞ i^r

Commented byDwaipayan Shikari last updated on 10/Jul/20

(i+i^2 +i^3 +i^4 +.....)=(i/(1−i))  (1+i+i^2 +i^3 +......)=(1/(1−i))  (i/(1−i))+(1/(1−i))=i