Cho A= 1 + 1/2 + 1/3 + 1/4 + ... 1/2mũ100 -1
CM: 50 < A < 100
1.Cho:
A=1/1^2+1/2^2+1/3^2+1/4^2+...+1/50^2
CM A<2
Cho A = 1/3^2 + 1/4^2 + 1/5^2 + ... + 1/50^2
CM rằng A > 1/4
Cho A =1/1^2+1/2^2+1/3^2+……+1/50^2
Cm A<2
A=\(\frac{1}{^22}+\frac{1}{^23}+\frac{1}{^2\text{4}}+......+\frac{1}{^2100}\)
Chứng minh hơn 3/4
B=\(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+......+\frac{1}{100^2}\)<1
Cho A=1/2²+1/2³+1/3²+1/4²+...+1/50² Chứng minh A
a)E=12/84 + 12/210 + 12/390 +...+ 12/2100
b)G=1/2 + 1/22 + 1/23 + 1/24 +....+ 1/299 + 1/2100
Cho A = 1/3 mũ 2 +1/4 mũ 2 +...+1/50 mũ 2. Chứng minh rằng 1/4 < A < 4
Bài 5: (1 điểm) Cho A= 2+22+23+24+.....+2100 . Chứng minh A chia hết cho 3.