Răspuns:
s=1+1/2+1/2²+....+1/2²⁰⁰⁸
2s=2+1+1/2+1/2²+...+1/2²⁰⁰⁷
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2s-s=2+1+1/2+1/2²+;::+1/2²⁰⁰7-(1-1/2-1/2²+...+1/2²⁰⁰⁷+1/2²⁰⁰⁸)=
s=2+1/2+1/2²+....+1/2²⁰⁰⁷-1-1/2-1/2²-...-1/2²⁰⁰⁷-1/2²⁰⁰⁸=
2-1/2²⁰⁰⁸<2
s∈(1,2)
Explicație pas cu pas: