12^55

=(3.2^2)^55

=3.2^57 > 2^57

hok tốt

k vs mik chưa đc k nào

Ta có: 12⁵⁵ = ( 2.6 )⁵⁵ = 2⁵⁵ . 6⁵⁵

           2⁵⁷ = 2⁵⁵ . 2²

Vì 2⁵⁵ = 2⁵⁵ nên ta so sánh 6⁵⁵ và 2² mà chắc chắn 6⁵⁵ > 2² nên 12⁵⁵ > 2⁵⁷.

Ta có: 1255 = ( 2.6 )55 = 255 . 655

           257 = 255 . 22

Vì 255 = 255 nên ta so sánh 655 và 22 mà chắc chắn 655 > 22 nên 1255 > 257.

12/32<27/55

nhớ l i k e

Lời giải:

\(A=\frac{98^{12}+1}{98^{13}+1}\\ 98A=\frac{98^{13}+98}{98^{13}+1}=1+\frac{97}{98^{13}+1}> 1+\frac{97}{98^{14}+1}=\frac{98^{14}+98}{98^{14}+1}=98.\frac{98^{13}+1}{98^{14}+1}=98B\)

$\Rightarrow A>B$

A = \(\frac{3}{2}+\frac{7}{6}+\frac{13}{12}+...+\frac{91}{90}+\left(1+\frac{1}{2}\right)+\left(1+\frac{1}{6}\right)+\left(1+\frac{1}{12}\right)+...+\left(1+\frac{1}{90}\right)\)

\(=\left(1+\frac{1}{1.2}\right)+\left(1+\frac{1}{2.3}\right)+\left(1+\frac{1}{3.4}\right)+...+\left(1+\frac{1}{9.10}\right)\)

\(=\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{9.10}\right)+\left(1+1+1+...+1\right)\)(9 số hạng 1)

\(=\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{9}-\frac{1}{10}\right)+1.9\)

\(=\left(1-\frac{1}{10}\right)+9=10-\frac{1}{10}=\frac{99}{10}>\frac{98}{11}\)

a=1+1/1.2+1+1+1/2.3+....+1+1/9.10

a=1+1+...+1(9 chữ số 1)+1/1-1/2+1/2-1/3+...+1/9-1/10

a=9+1-1/10

a=9+9/10=9+0.9=9.9

b=98/11<98/10=9.8<9.9

=>vậy a>b

\(\frac{4}{6}=\frac{2}{3}\)

\(\frac{18}{27}=\frac{2}{3}\)

\(\Rightarrow\frac{4}{6}=\frac{18}{27}\)

\(\frac{12}{20}=\frac{3}{5}\)

\(\frac{22}{55}=\frac{2}{5}\)

\(\Rightarrow\frac{12}{20}>\frac{22}{55}\)

\(\frac{5}{6}=\frac{10}{12}\)

\(\Rightarrow\frac{5}{6}< \frac{11}{12}\)

Sắp xếp :

4;5;7;8;15;56

HT

\(\frac{4}{6}=\frac{2}{3}\)

\(\frac{18}{27}=\frac{2}{3}\)

\(\Rightarrow\frac{4}{6}=\frac{18}{27}\)

\(\frac{12}{20}=\frac{3}{5}\)

\(\frac{22}{55}=\frac{2}{5}\)

\(\Rightarrow\frac{12}{20}>\frac{22}{55}\)

\(\frac{5}{6}=\frac{10}{12}\)

\(\Rightarrow\frac{5}{6}< \frac{11}{12}\)

Sắp xếp:

4; 5; 7; 8; 15; 56.

_HT_

97/98 < 2018/2019

-25/26 < -18/31

-9/11 > -13/12

a=1+1/1.2+1+1/2.3+....+1+1/9.10

a=1+1+...+1(9 chữ số 1) +1/1-1/2+1/2-1/3+..+1/9-1/10

a=9+1-1/10

a=9+9/10=9+0.9=9.9

b=98/11<98/10=9.8<9.9.

vậy a>b

Ta có: a=1+1/2+1+1/6+1+1/12+...+1+1/90=9+1/2+1/6+...+1/90 > 9>99/11> b. Vậy, a>b

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