Let

s ≡ 1 + α+ α2 + α3 + α4 + …,

αs = α+ α2 + α3 + α4 + …,

Hence,

(1 − α) s = 1,

and

s = 1 1− α .

---

File translated from T_EX by T_TH, version 4.03.
On 13 Jun 2022, 12:41.