a)1/2+1/2^2+1/2^3+1/2^4+……..+1/2^n <1 b)1/2^2+1/3^2+1/4^2+ ... +1/10^2 <1 12/08/2021 Bởi Josephine a)1/2+1/2^2+1/2^3+1/2^4+……..+1/2^n <1 b)1/2^2+1/3^2+1/4^2+ ... +1/10^2 <1
b) 1/2^2+1/3^2+…+1/10^2<1 1/2^2+1/3^2+…+1/10^2<1/1*2+1/2*3+1/3*4+…+1/9*10 <1/1-1/2+1/2-1/3+1/3-1/4+…+1/9-1/10 <1/1-1/10 <9/10<1 =>1/2^2+1/3^2+…+1/10^2<1 Bình luận
b) 1/2^2+1/3^2+…+1/10^2<1
1/2^2+1/3^2+…+1/10^2<1/1*2+1/2*3+1/3*4+…+1/9*10
<1/1-1/2+1/2-1/3+1/3-1/4+…+1/9-1/10
<1/1-1/10
<9/10<1
=>1/2^2+1/3^2+…+1/10^2<1
Xin ctlhn