ta có 

\(1+3+3^2+..+3^{2000}=\left(1+3+3^2\right)+\left(3^3+3^4+3^5\right)+..+\left(3^{1998}+3^{1999}+3^{2000}\right)\)

\(=13.1+13\cdot3^3+..+13\cdot3^{1998}\) chia hết cho 13

tương tự

\(1+4+4^2+..+4^{2012}=\left(1+4+4^2\right)+..+\left(4^{2010}+4^{2011}+4^{2012}\right)\)

\(=21.1+21\cdot4^3+..+21.4^{2010}\) chia hết cho 21

=2

nha bn

hok tốt

bằng 2

1 + 1 = 2

k mk nha

a,

`3A=3+3^3+3^3+...+3^{53}`

`3A-A=(3+3^3+3^3+...+3^{53})-(1+3+3^3+3^3+...+3^{52})`

`2A=3^{53}-1`

`A=(3^{53}-1)/2`

b,

`A=1+3+3^3+3^3+...+3^{52}`

`A=(1+3+3^2)+(3^3+3^4+3^5)+....+(3^{50}+3^{51}+3^{52})`

`A=(1+3+3^2)+3^3*(1+3+3^2)+....+3^{50}*(1+3+3^2)`

`A=(1+3+3^2)*(1+3^3+....+3^{50})`

`A=13*(1+3^3+....+3^{50})`

Do `13 \vdots 13 => A=13*(1+3^3+....+3^{50})\vdots 13 `

Vậy `A \vdots 13 `

\(\frac{2015^{35}+1}{2015^{34}+1}=\frac{2015^{35}+2015-2014}{2015^{34}+1}=\frac{2015\left(2015^{34}+1\right)-2014}{2015^{34}+1}=\frac{2015\left(2015^{34}+1\right)}{2015^{34}+1}-\frac{2014}{2015^{34}+1}=2015-\frac{2014}{2015^{34}+1}\)

\(\frac{2015^{34}+1}{2015^{33}+1}=\frac{2015^{34}+2015-2014}{2015^{33}+1}=\frac{2015\left(2015^{33}+1\right)-2014}{2015^{33}+1}=\frac{2015\left(2015^{33}+1\right)}{2015^{33}+1}-\frac{2014}{2015^{33}+1}=2015-\frac{2014}{2015^{33}+1}\)

Mà \(2015-\frac{2014}{2015^{34}+1}>2015-\frac{2014}{2015^{33}+1}\)

Vậy\(\frac{2015^{35}+1}{2015^{34}+1}>\frac{2015^{34}+1}{2015^{33}+1}\)

CẢM ƠN BẠN RẤT ẤT ẤT T T T .... NHIỀU

làm

1+1=2

mik là girl 2k6

làm

1+1=2

hok tốt

1 + 1 = 2

Hok tốt

# ĐLoveP #

C = 1/2*(1/1 - 1/3 + 1/3 - .... - 1/23)

C=  1/2*(1-  1/23)

C = 1/2 * 22/23

C = 11/23

C=1/1*3+1/3*5+1/5*7......+1/21*23

C=1/2*(1-1/23)

C=1/2*22/23

C=11/23

tick nha

=00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

=00000000000000000000000000000000000000000000

2 

kb nha

1+1=2

bn chs mini world k 

 1 + 1 = 2

  1 + 1 = 2

1 + 1 = 2

\(1+1-1=1\)

1 + 1 - 1 = 1

tớ là boy nhưng vẫn thích trả lời

1+1-1=1

Tui girl nè