Question

[Little Rose]

a) 1/2 - 1/4 + 1/8 - 1/16 + 1/32 - 1/64 < 1/3

b) 1/3 - 2/3² + 3/3³ - 4/3⁴ +...+ 99/3⁹⁹ - 100/3¹⁰⁰ < 3/16

Answer 1

[Nguyễn Văn An]

a,=1/4+1/16+1/64=16/64+4/64+1/64=21/64<21/63=1/3

   suy ra 1/2-1/4+1/8-1/16+1/32-1/64<1/3