K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

15 tháng 10 2019

Ta có:

\(\left(\frac{1}{16}\right)^{250}=\left(\frac{1}{16}\right)^{250}.\)

\(\left(\frac{1}{2}\right)^{1500}=\left[\left(\frac{1}{2}\right)^6\right]^{250}=\left(\frac{1}{64}\right)^{250}.\)

\(\frac{1}{16}>\frac{1}{64}\) nên \(\left(\frac{1}{16}\right)^{250}>\left(\frac{1}{64}\right)^{250}.\)

\(\Rightarrow\left(\frac{1}{16}\right)^{250}>\left(\frac{1}{2}\right)^{1500}.\)

Chúc bạn học tốt!

17 tháng 6 2015

(1/2)1500=(1/26)250=(1/64)250

Do 1/16>1/64 =>(1/16)250>(1/64)250

Vậy (1/16)250>(1/2)1500

17 tháng 6 2015

\(\left(\frac{1}{16}\right)^{250}\) và \(\left(\frac{1}{2}\right)^{1500}\)

=> \(\left(\frac{1}{16}\right)^{250}\) và \(\left(\left(\frac{1}{2}\right)^6\right)^{250}\)

=> \(\frac{1}{16}\) và \(\left(\frac{1}{2}\right)^6\)

=> \(\frac{1}{16}\) và \(\frac{1}{64}\)

=>  \(\frac{1}{16}\) >  \(\frac{1}{64}\)  hay  \(\left(\frac{1}{16}\right)^{250}\) >  \(\left(\frac{1}{2}\right)^{1500}\)

 

Bài 1:

Ta có:

\(\left(\frac{1}{10}\right)^{15}=\left(\frac{1}{5}\right)^{3.5}=\left(\frac{1}{125}\right)^5\)

\(\left(\frac{3}{10}\right)^{20}=\left(\frac{3}{10}\right)^{4.5}=\left(\frac{81}{10000}\right)^5\)

Lại có:

\(\frac{1}{125}=\frac{80}{10000}< \frac{81}{10000}\Rightarrow\left(\frac{1}{125}\right)^5< \left(\frac{81}{10000}\right)^5\)

\(\Rightarrow\left(\frac{1}{10}\right)^{15}< \left(\frac{3}{10}\right)^{20}\)

Bài 2:

Ta có:

\(A=\frac{13^{15}+1}{13^{16}+1}\Rightarrow13A=\frac{13^{16}+13}{13^{16}+1}=1+\frac{12}{13^{16}+1}\)

\(B=\frac{13^{16}+1}{13^{17}+1}\Rightarrow13B=\frac{13^{17}+13}{13^{17}+1}=1+\frac{12}{13^{17}+1}\)

\(\frac{12}{13^{16}+1}>\frac{12}{13^{17}+1}\)

\(\Rightarrow1+\frac{12}{13^{16}+1}>1+\frac{12}{13^{17}+1}\)

\(\Rightarrow13A>13B\Rightarrow A>B\)

23 tháng 8 2018

Ta có : \(A=\left(1-\frac{1}{2}\right)\left(1-\frac{1}{3}\right)...\left(1-\frac{1}{19}\right)\left(1-\frac{1}{20}\right)\)

               \(=\frac{1}{2}.\frac{2}{3}....\frac{18}{19}.\frac{19}{20}\)

               \(=\frac{1.2....18.19}{2.3...19.20}\)

               \(=\frac{1}{20}>\frac{1}{21}\)

Vậy A > 1/21

3 tháng 5 2018

\(A=\left(\frac{1}{4}-1\right)\left(\frac{1}{9}-1\right)\left(\frac{1}{16}-1\right)...\left(\frac{1}{400}-1\right)\)

\(-A=\left(1-\frac{1}{4}\right)\left(1-\frac{1}{9}\right)\left(1-\frac{1}{16}\right)...\left(1-\frac{1}{400}\right)\)

\(-A=\frac{3}{4}\cdot\frac{8}{9}\cdot\frac{15}{16}\cdot...\cdot\frac{399}{400}\)

\(-A=\frac{1\cdot3}{2\cdot2}\cdot\frac{2.4}{3.3}\cdot\frac{3.5}{4.4}\cdot...\cdot\frac{19.21}{20.20}\)

\(-A=\frac{1\cdot2\cdot3\cdot...\cdot19}{2\cdot3\cdot4\cdot...\cdot20}\cdot\frac{3\cdot4\cdot5\cdot...\cdot21}{2\cdot3\cdot4\cdot...\cdot20}\)

\(-A=\frac{1}{20}\cdot\frac{21}{2}=\frac{21}{40}>\frac{20}{40}=\frac{1}{2}\)

\(-A>\frac{1}{2}\Rightarrow A< \frac{1}{2}\)

17 tháng 7 2016

Ta có:

\(\left(\frac{1}{16}\right)^{50}=\left[\left(\frac{1}{2}\right)^4\right]^{50}=\left(\frac{1}{2}\right)^{200}=\frac{1^{200}}{2^{200}}=\frac{1}{2^{200}}\)

\(\left(\frac{1}{2}\right)^{60}=\frac{1^{60}}{2^{60}}=\frac{1}{2^{60}}\)

Vì \(2^{200}>2^{60}\Rightarrow\frac{1}{2^{200}}< \frac{1}{2^{60}}\Rightarrow\left(\frac{1}{16}\right)^{50}< \left(\frac{1}{2}\right)^{60}\)

17 tháng 7 2016

Ta có:

\(\left(\frac{1}{16}\right)^{50}=\left(\frac{1}{2}\right)^{4.50}=\left(\frac{1}{2}\right)^{200}\)

\(\Rightarrow\left(\frac{1}{2}\right)^{500}>\left(\frac{1}{2}\right)^{60}\)

\(\Rightarrow\left(\frac{1}{16}\right)^{50}>\left(\frac{1}{2}\right)^{60}\)

26 tháng 7 2019

\(x=\left(1-\frac{1}{2}\right).\left(1-\frac{1}{4}\right)\left(1-\frac{1}{6}\right)\left(1-\frac{1}{8}\right)\left(1-\frac{1}{10}\right)\)

\(=\frac{1}{2}.\frac{3}{4}.\frac{5}{6}.\frac{7}{8}.\frac{9}{10}=\frac{63}{256}< \frac{63}{210}=0,3\)

\(x=\sqrt{0,1}>\sqrt{0,09}=0,3\)

=> y<x

10 tháng 10 2017

Ta có :

\(M=\frac{3}{4}.\frac{8}{9}.\frac{15}{16}.....\frac{99}{100}=\frac{3.8.15.....99}{4.9.16.....100}=\frac{1.3.2.4.3.5.....9.11}{2.2.3.3.4.4.....10.10}\)\(=\frac{1.2.3...9}{2.3...10}.\frac{3.4...11}{2.3...10}=\frac{1}{10}.\frac{11}{2}=\frac{11}{20}< \frac{11}{19}\)

ta có M = (1- 1/4) (1- 1/9)... ( 1- 1/100)

             = 3/2^2.8/3^2 ... 99/10^2

             = 1.3/2^2 . 2.4/3^2 ... 9.11/10^ 2

             = 1.2.3...9/ 2.3.4...10 . 3.4.5... 11/ 2.3.4... 10

             = 1/10 . 11/2 = 11/20 < 11/19

              Vậy M < 11/19