A=20^10+1/20^10-1

A=20^10-1+2/20^10-1

A=20^10-1/20^10-1+2/20^10-1

A=1+2/20^10-1

B=20^10-1/20^10-3

B=20^10-3+2/20^10-3

B=20^10-3/20^10-3+2/20^10-3

B=1+2/20^10-3

Vì 20^10-1>20^10-3 nên 2/20^10-1<2/20^10-3

=>A<B

Ta có: \(20^{10}-1>20^{10}-3\)

\(\Rightarrow\frac{20^{10}-1}{20^{10}-3}>1\)

\(\Rightarrow\frac{20^{10}-1}{20^{10}-3}>\frac{20^{10}-1+2}{20^{10}-3+2}=\frac{20^{10}+1}{20^{10}-1}=B\)

Vậy \(A>B\)

Ta thấy B=20^10-1/20^10-3 là phân số lớn hơn 1.

Theo tính chất nếu a/b>1 thì a/b > a+n/b+n ( n khác 0 )

Ta có : 20^10-1/20^10-3 > 20^10-1+2/20^10-3+2

          <=> B > 20^10+1/20^10-3 = A

          <=> B > A

          Vậy B > A    

Lời giải:

$A=\frac{20^{10}-1+2}{20^{10}-1}=1+\frac{2}{20^{10}-1}$

$B=\frac{20^{10}-3+2}{20^{10}-3}=1+\frac{2}{20^{10}-3}$

Vì $20^{10}-1> 20^{10}-3$

$\Rightarrow \frac{2}{20^{10}-1}< \frac{2}{20^{10}-3}$

$\Rightarrow 1+\frac{2}{20^{10}-1}< 1+\frac{2}{20^{10}-3}$

$\Rightarrow A< B$

\(A=\frac{2010+1}{2010-1}\)

\(A=1+\frac{2}{2010-1}>1\)

\(B=\frac{2010-1}{2010-3}\)

\(B=1-\frac{2}{2010-3}<1\)

Từ đó A > B

Ta thấy : A =\(\frac{20^{10}+1}{20^{10}-1}>1\) 
Ta có : A=\(\frac{20^{10}+1}{20^{10}-1}>\frac{20^{10}+1-2}{20^{10}-1-2}=\frac{20^{10}-1}{20^{10}-3}=B\)
Vậy A > B

cám ơn bạn

Theo đề ta có:

A= 20^10+1/20^10-1 (1)

Từ (1) ta có: 20^10+1/20^10-1>20^10+1-2/20^10-1-2=20^10-1/20^10-3=B.

Vậy A>B

Ta thấy:\(A=\frac{20^{10}+1}{20^{10}-1}>1\)

Ta có: \(A=\frac{20^{10}+1}{20^{10}-1}>\frac{20^{10}+1-2}{20^{10}-1-2}=\frac{20^{10}-1}{20^{10}-3}=B\)

Vậy \(A>B\)

mk dịch hộ bạn đề cho dễ làm,bạn xem xem mk dịch đúng ko nhé:

\(A=20^{10}+\left(\frac{1}{20}\right)^{10}-1\)

\(B=20^{10}-\left(\frac{1}{20}\right)^{10}-3\)