S=1/5^2 - 2/5^3 + 3/5^4 -...+99/5^100-100/5^101
CMR S<1/3^6
A=1/2^2 + 1/4^2 + 1/6^3 + ... +1/100^2 . CMR A<1/2
CMR:(1+1/2+1/3+1/4+...+1/100)=1/2=2/3+3/4+...+99/100
Bài 1 : Tính tổng
a) 1 *2 *3 + 2 * 3 *4 + 3 * 4 * 5 + ... + 2013 * 2014 * 2015 + 2014 * 2015 * 2016
b) 1 * + 3 * 4 + 5 * 6 + ... + 99 * 100
Bài 2 : CMR : 1^3 + 2^3 + 3^3 + ... + n^3 = ( 1 + 2 + 3 + ... + n )^2
Cho T=1/32 - 1/34 + 1/36 - ... - 1/3100. CMR T<0,1
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
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
CMR: (1*3*5*....*99)/(2*4*6*....*100)<1/10