9.2^x.(2^1005-2^1002+.....+2^3-1)=2^1008-1 *

A=2^1005-2^1002+...+2^3-1 2^3 .

A=2^2.(2^1005-2^1002+......+2^3-1) 8.

A=2^1008-2^1005+.....+2^6-2^3

A=2^1005-2^1002+.....+2^3-1 8.A+A=2^1008-1 9.

A=2^1008-1

Thay 9.a=2^1008-1 vào * ta có: 2^x.(2^1008-1)=2^1008-1

2^x=(2^1008-1):(2^1008-1)

2^x=1 

2^x=2^0 

x=0

vậy x=0

Lập đề bài cho bài toán này

x - 1/1+2 - 1/1+2+3 - 1/1+2+3+4 - ...... - 1/1+2+3+......+2015=1/1008

(1 + 1/2) x (1 + 1/3) x (1 + 1/4) x (1 + 1/x) = 1008 x 1/2

\(\frac{1}{2}-\left(\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+...+\frac{1}{1+2+3+...+x}\right)=-\frac{503}{1008}\)tìm x

​\(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2^{2016}-2}+\frac{1}{2^{2016}-1}>1008\)​​

\(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2^{2016}-2}+\frac{1}{2^{2016}-1}>1008\)​

c1: \(\frac{1}{2}-\left(\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+...+\frac{1}{1+2+3+...+x}\right)=-\frac{503}{1008}\)

A=1/1*2 + 1/3*4 + 1/5*6 + ... +1/2013*2014

B=1/1008*2014 + 1/1009*2013 + 1/1010*2012+ ... + 1/2014*1008

B=1 + 1/2 + 1/3 + 1/4 +1/5 + .....+ 1/2²⁰¹⁶ - 2 + 1/2²⁰¹⁶ - 1 > 1008

Tìm x

(\(\left(1+\frac{1}{2}\right)x\left(1+\frac{1}{3}\right)x\left(1+\frac{1}{4}\right)x...x\left(1+\frac{1}{x}\right)=1008\frac{1}{2}\)