Question

[ninhthidieulinh]

Tính 

A=1/2-1/2²+1/2⁴+...+1/2⁹⁹-1/2¹⁰⁰

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Answer 1

[Bye My Love]

2A=1-1/2+1/2^3+...+1/2^98-1/2^99

2A-A=(1-1/2+...+1/2^98-1/2^99)-(1/2-1/2^2+...+1/2^99-1/2^100)

A=1+1/2^100