Bạn chưa đăng nhập. Vui lòng đăng nhập để hỏi bài

Những câu hỏi liên quan
Duc Huy Doan
Xem chi tiết
Nguyễn Hà Giang
Xem chi tiết
Nguyễn Thị Hương Giang
Xem chi tiết
Lê Thị Lệ Thúy
Xem chi tiết
Ngo Tung Lam
18 tháng 3 2018 lúc 20:04

Ta có :

\(A=\frac{10^{2016}+1}{10^{2015}+1}=\frac{\left(10^{2016}+1\right).10}{\left(10^{2015}+1\right).10}=\frac{10^{2017}+10}{10^{2016}+10}=\frac{10^{2017}+10}{10^{2016}+10}\)

Vì \(10^{2017}=10^{2017}\)\(10>1\)nên \(10^{2017}+10>10^{2017}+1\)( 1 )

Vì \(10^{2016}=10^{2016}\)và \(10>1\)nên \(10^{2016}+10>10^{2016}+1\)( 2 )

Từ ( 1 ) và ( 2 ) , suy ra : \(\frac{10^{2017}+10}{10^{2016}+10}>\frac{10^{2017}+1}{10^{2016}+1}\)

Vậy \(A>B\)

NGuyễn Ngọc Hạ Vy
18 tháng 3 2018 lúc 20:16

\(B=\frac{10^{2016}+1}{10^{2017}+1}=\frac{10^{2016}+1+9}{10^{2017}+1+9}=\frac{10^{2016}+10}{10^{2017}+10}=\frac{10.\left(10^{2015}+1\right)}{10.\left(10^{2016}+1\right)}=\frac{10^{2015}+1}{10^{2016}+1}\)

lm tương tự vs B ta có 

\(A=\frac{10^{2015}+1}{10^{2014}+1}\)

suy ra A>B

Bùi Hồng Anh
18 tháng 3 2018 lúc 20:28

Ta có: A=\(\frac{10^{2016}+1}{10^{2015}+1}\)

=>\(\frac{1}{A}=\frac{10^{2015}+1}{10^{2016}+1}=\frac{10\left(10^{2015}+1\right)}{10\left(10^{2016}+1\right)}=\frac{10^{2016}+10}{10\left(10^{2016}+1\right)}=\frac{10^{2016}+1+9}{10\left(10^{2016}+1\right)}\)

           \(=\frac{1}{10}+\frac{9}{10^{2017}+10}\)

         \(B=\frac{10^{2017}+1}{10^{2016}+1}\)

=>\(\frac{1}{B}=\frac{10^{2016}+1}{10^{2017}+1}=\frac{10\left(10^{2016}+1\right)}{10\left(10^{2017}+1\right)}=\frac{10^{2017}+10}{10\left(10^{2017}+1\right)}\)

           \(=\frac{10^{2017}+1+9}{10\left(10^{2017}+1\right)}=\frac{1}{10}+\frac{9}{10^{2018}+10}\)

\(10^{2017}< 10^{2018}=>10^{2017}+10< 10^{2018}+10\)

\(=>\frac{9}{10^{2017}+10}>\frac{9}{10^{2018}+10}=>\frac{1}{10}+\frac{9}{10^{2017}+10}>\frac{1}{10}+\frac{9}{10^{2017}+10}\)

\(=>\frac{1}{A}>\frac{1}{B}=>A< B\)

Khởi My Lovely
Xem chi tiết
Hoàng Phúc
13 tháng 5 2016 lúc 20:02

\(A=\frac{10^{2015}+1}{10^{2016}+1}\Rightarrow10A=\frac{10.\left(10^{2015}+1\right)}{10^{2016}+1}=\frac{10^{2016}+10}{10^{2016}+1}\)

\(A=\frac{10^{2016}+1+9}{10^{2016}+1}=\frac{10^{2016}+1}{10^{2016}+1}+\frac{9}{10^{2016}+1}=1+\frac{9}{10^{2016}+1}\)

\(B=\frac{10^{2016}+1}{10^{2017}+1}\Rightarrow10B=\frac{10.\left(10^{2016}+1\right)}{10^{2017}+1}=\frac{10^{2017}+10}{10^{2017}+1}\)

\(B=\frac{10^{2017}+1+9}{10^{2017}+1}=\frac{10^{2017}+1}{10^{2017}+1}+\frac{9}{10^{2017}+1}=1+\frac{9}{10^{2017}+1}\)

Vì 102016+1 < 102017+1

=>\(\frac{9}{10^{2016}+1}>\frac{9}{10^{2017}+1}\)

=>\(1+\frac{9}{10^{2016}+1}>1+\frac{9}{10^{2017}+1}\)

=>10A > 10B

=>A > B

TFBoys_Thúy Vân
13 tháng 5 2016 lúc 20:07

\(B=\frac{10^{2016}+1}{10^{2017}+1}<\frac{10^{2016}+1+9}{10^{2017}+1+9}\)

      \(=\frac{10^{2016}+10}{10^{2017}+10}\)

      \(=\frac{10.\left(10^{2015}+1\right)}{10.\left(10^{2016}+1\right)}\)

      \(=\frac{10^{2015}+1}{10^{2016}+1}=A\)

\(\Rightarrow\) B<A

Thắng Nguyễn
13 tháng 5 2016 lúc 20:07

\(10A=\frac{10\left(10^{2015}+1\right)}{10^{2016}+1}=\frac{10^{2016}+10}{10^{2016}+1}=\frac{10^{2016}+1+9}{10^{2016}+1}=\frac{10^{2016}+1}{10^{2016}+1}+\frac{9}{10^{2016}+1}=1+\frac{9}{10^{2016}+1}\)

\(10B=\frac{10\left(10^{2016}+1\right)}{10^{2017}+1}=\frac{10^{2017}+10}{10^{2017}+1}=\frac{10^{2017}+1+9}{10^{2017}+1}=\frac{10^{2017}+1}{10^{2017}+1}+\frac{9}{10^{2017}+1}=1+\frac{9}{10^{2017}+1}\)

vì 102016+1<102017+1

=>\(\frac{9}{10^{2016}+1}>\frac{9}{10^{2017}+1}\)

=>A>B

Nguyễn Trà My
Xem chi tiết
Thanh Hằng Nguyễn
26 tháng 8 2017 lúc 14:14

Áp dung công thức \(a>b\Leftrightarrow\frac{a}{b}>\frac{a+m}{b+m}\)

\(B=\frac{10^{2017}+1}{10^{2016}+1}>\frac{10^{2017}+1+9}{10^{2016}+1+9}=\frac{10^{2017}+10}{10^{2016}+10}=\frac{10\left(10^{2016}+1\right)}{10\left(10^{2015}+1\right)}=\frac{10^{2016}+1}{10^{2015}+1}=A\)

\(\Leftrightarrow B>A\)

Vũ Quốc Việt
Xem chi tiết
Hoàng Thị Trà My
Xem chi tiết
Nguyễn Thị Mỹ Hoa
Xem chi tiết
Nguyễn Thị Mỹ Hoa
4 tháng 3 2016 lúc 20:12

cách giải