Y
yubin_cute


1.Chứng minh 1/3 - 2/(3^2) + 3/(3^3) - 4/(3^4) + ... + 99/(3^99) - 100/(3^100) < 3/16
2.Chứng minh A=1/2 - 1/4 + 1/8 + 1/16 + 1/32 - 1/64 < 1/3
2.Chứng minh A=1/2 - 1/4 + 1/8 + 1/16 + 1/32 - 1/64 < 1/3