1/1= 1 Nên S= 1/1+2 +1/1+2+3 +...+1/1+2+3+...+2013 =1+2+1+2+3+....1+2+3+...+2013 S+1= 1+1+2+1+2+3+....+1+2+3+...+2013 =1 x2013+2 x2012+...+2012x2+02013 x1 Có 1 SH chỉ XH 1 lần đó là 1007 tính tổng trừ 1
Hãy chứng minh A = B , biết:
A = 1 + (1+ 2) + (1+ 2+ 3) + ...........+ ( 1+ 2+ 3+ 4+ ...+ 2013)
B = 2013 x 1 + 2012 x 2 + 2011 x 3 + ......+ 2 x 2012 + 1 x 2013
Tính nhanh (1/1):2+(1/2):3+1/3:4+...+(1/2012):2013+(1/2013):2014
S= 1/1+2 +1/1+2+3 +...+1/1+2+3+...+2013
Tính K + 2013, biết:
K=\(\frac{1+\left(1+2\right)+\left(1+2+3\right)+...+\left(1+2+3+...+2013\right)}{2013\times1+2012\times2+2011\times3+...+2\times2012+1\times2013}\)
k=\(\frac{1+\left(1+2\right)+\left(1+2+3\right)+...+\left(1+2+3+...+2013\right)}{2013\cdot1+2012\cdot2+2011\cdot3+...+2\cdot2012+1\cdot2013}\)
a)S = 1 + 1/3 + 1/9 + 1/27 + ..................... + 1/2187
b)S = 1 + 1/2 + 1/4 + 1/8 + ..................... + 1/128 + 1/256
c)A = 1 + 2 + 4 + 8 + ..................... + 4096 + 8192
d)1/1 x2 + 1/ 2 x 3 + 1/ 3 x 4 + ................. + 1/ 2013 x 2014
h)A = 1/1 x3 + 1/ 3 x 5 + 1/ 5 x 7 + ................. + 1/ 2013 x 2015
bai2a)1/ 2 x (1 + 2) + 1/ 2 x (1 + 2 + 3) + ............ + 1/2 x (1 + 2 + 3 + ....... + 9)
ai nhanh tick đúng nha
1/1×2+1/2×3+1/3×4 + 1/4×5 +..........+ 1/ 2012×2013
Hãy so sánh M và N biết:
M = 1 2014 + 2 2013 + 3 2012 + ... + 2014 1
N = 1 + (1 + 2) + (1 + 2 + 3) + ... + (1 + 2 + 3 + ... + 2014)
tính K biết
K=1+(1+2)+(1+2+3)+...+(1+2+3+...+2013)
