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\(1990^{10}>1990^9\left(1\right)\)
Ta có \(1991^1=1990^1+1990^0\)
mà \(\)\(1990^1+1990^0< 1990^9\left(1990>1\right)\)
\(\Rightarrow1990^9>1991^1\left(2\right)\)
\(\left(1\right),\left(2\right)\Rightarrow1991^1< 1990^9< 1990^{10}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta rút gọn hai phân số rồi so sánh:
\(\frac{200420042004}{200520052005}\) = \(\frac{200420042004:100010001}{200520052005:100010001}\) = \(\frac{2004}{2005}\)
\(\frac{20042004}{20052005}\) = \(\frac{20042004:10001}{20052005:10001}\)= \(\frac{2004}{2005}\)
Ta thấy: \(\frac{2004}{2005}\)= \(\frac{2004}{2005}\)
Vậy: hai phân số này bằng nhau
ta có:
\(\frac{200420042004}{200520052005}=\frac{200420042004:100010001}{200520052005:100010001}=\frac{2004}{2005}\)
\(\frac{20042004}{20052005}=\frac{20042004:10001}{20052005:10001}=\frac{2004}{2005}\)
\(\Rightarrow\frac{200420042004}{200520052005}=\frac{20042004}{20052005}\)
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ta có:
\(5^4=625\)
\(4^5=1024\)
vì \(625< 1024\)nên
\(\Rightarrow5^4< 4^5\)
\(\frac{5}{4}\)>1
\(\frac{4}{5}\)<1
suy ra \(\frac{4}{5}\)<1\(\frac{5}{4}\)
vay \(\frac{4}{5}\)<\(\frac{5}{4}\)
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3117<3217; 3217=(25)17=251
1714>1614; 1614=(24)14=256
Vì 251<256=>3217<1614
=>3117<1714
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35=3.3.3.3.3=243
53=5.5.5=125
Vì: 243> 125=> 35> 53 (điều phải chứng minh)
35=3.3.3.3.3=243
53=5.5.5=125
Vì: 243> 125=> 35> 53 (điều phải chứng minh)
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\(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+\frac{1}{7}+\frac{1}{8}<\frac{1}{2}+\frac{1}{2}+\frac{1}{4}+\frac{1}{4}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}=2.\frac{1}{2}+2.\frac{1}{4}+3.\frac{1}{6}=2\)
222333 = (2223)111 = (23 . 1113)111 = (8 . 111 . 1112)111 = (888 . 1112)111
333222 = (3332)111 = (32 . 1112)111 = (9 . 1112)111
=> 222333 > 333222
222333=(2223)111
333222=(3332)111
Mà 2223=10941048
3332=110889
=>2223>3332
=>222333>333222