Các câu hỏi tương tự
chứng minh
1/22+1/32+1/42+1/52+...+1/1002 >3/4
M = 1002– 992 + 982 – 972 + … + 22 – 12;
N = (202+ 182 + 162 + … + 42 + 22) – (192 + 172 + 152 + … + 32 + 12);
P = (-1)n.(-1)2n+1.(-1)n+1.
1/22 + 1/42 + 1/62 + 1/82 + ... + 1/20222 < 1/2 (gần gấp)
let S be 1!(12+1+1)+2!(22+2+1)+3!(32+3+1)+...+100!(1002+100+1). Find S+1/101!.(as usual, k! = 1.2.3.....(k-1).k)
B1 a) A=5+53+55+57+..........+5101
b)B=1-1/72-1/73+..........+1/2016
B2 Chứng minh rằng 1/6<1/52+1/62+....+1/1002
B3 Chứng minh rằng 1/n3<1/(n-1)n(n+1)
Chứng minh rằng:
A = 1/3 + 1/32 + 1/33 + ..........+ 1/399 < 1/2
B = 3/12x 22 + 5/22 x 32 + 7/32 x 42 +............+ 19/92 x 102 < 1
C = 1/3 + 2/32 + 3/33 + 4/34 +.........+ 100/3100 ≤ 0
CMR A < A^2 < 4 biết
A =1001/1002^+1 +1001/1002^2+2 +...+1001/1002^2+1000
biết:12+22+32+...+102=385.Tính tổng S=22+42+62+...+202
Cho12+22+32+...+82+92=285.Tính q=22+42+62+...+162+182
A = \(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+.....+\frac{1}{20^2}\)
cmr \(\frac{19}{42}< A< \frac{19}{22}\)