Question

[thanh]

cho A=1+1/2^2+1/3^2+1/4^2+.......+1/100^2 chứng minh rằng A<2

Answer 1

[✓ ℍɠŞ_ŦƦùM $₦G ✓]

1+1/2^2+1/3^2+1/4^2+...+1/100^2<1+1/1.2+1/2.3+1/3.4+.....+1/99.100=1+1-1/2+1/2-1/3+1/3-1/4+...+1/99-1/100

=2-1/100<2

=>đpcm