CMR:

a)1/10^2 +1/11^2+1/12^2+...+1/100^2 >3/4

b)1/2^2+1/3^2+1/4^2+...+1/100^2<99/100

c)1/2^2+1/3^2+1/4^2+...+1/100^2<3/4

a) Rút gọn biểu thức sau:

A=2*2^2+3*2^3+4*2^4+5*2^5+...+100*2^100

b) Cho B=1/2-1/3+1/4-1/5+...+1/98-1/99

CMR: 0,2< B < 0,4

CMR : a) 1/2! + 2/3! + 3/4! +...+ 99/100! < 1

b) 1.2-1/2! + 2.3-1/3! + 3.4-1/4! +...+ 99.100-1/100! < 2

Bài 1: CMR 3/1^2*2^2 + 5/2^2*3^2 + 7/3^2*4^2 + ....... + 19/9^2*10^2 bé hơn 1

Bài 2: CMR 1/3 + 2/3^2 Bài 1: CMR 3/1^2*2^2 + 5/2^2*3^2 + 7/3^2*4^2 + ....... + 19/9^2*10^2 bé hơn 3/4

Bài 3: Cho A= 1/1*2 + 1/3*4 + 1/5*6 + .... + 1/99*100. CMR 7/12 < A < 5/6

Bài 4 :

a,Cho A= 1/2!+1/3!+.....+1/100! 

CMR A<1

b, CMR :1-1/2+1/3-1/4+...+1/99-1/100=1/51+1/52+....+1/100

a) A = ( 1 + 1/2 + 1/3 + 1/4 +.......+ 1/100 ) mũ 2

CMR : A < 2

b) B = 1 + 1/2 + 1/3 + 1/4 +........+1/63

CMR : B < 6

giải hộ mik bài này cái

Cho B=1/2² +1/3²+....+1/100². Cmr B<3/4

CMR:

a)1/2-1/4+1/8-1/16+1/32-1/64<1/3

b)1/3 - 2/3^2 + 3/3^3 - 4/3^4 +...+ 99/3^99 -100/3^100 < 3/16

cmr

a) 1/2 -1/4+1/8-1/16+1/32-1/64 <1/3

b) 1/3-2/3^2+3/3^3-4/3^4+...+99/3^99-100/3^100<3/16