so sánh 17^4 và 31^11
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
Có 31^11>31^4
Mà 31^4>17^4(vì 31>17)
=> 31^11>17^4
Vậy 31^11>17^4
![](https://rs.olm.vn/images/avt/0.png?1311)
a/
2020.2021=(2019+1)(2022-1)=
=2019.2022-2019+2022-1=2019.2022+2>2019.2022
b/
\(4^7=\left(2^2\right)^7=2^{14}< 2^{15}\)
c/
\(199^{20}< 200^{20}=\left(8.25\right)^{20}=\left(2^3.5^2\right)^{20}=2^{60}.5^{40}\)
\(2000^{15}=\left(16.125\right)^{15}=\left(2^4.5^3\right)^{15}=2^{60}.5^{45}\)
\(\Rightarrow2000^{15}=2^{60}.5^{45}>2^{60}.5^{40}>199^{20}\)
d/
\(31^{31}< 32^{31}=\left(2^5\right)^{31}=2^{155}\)
\(17^{39}>16^{39}=\left(2^4\right)^{39}=2^{156}\)
\(\Rightarrow17^{39}=2^{156}>2^{155}>31^{31}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(31^{11}< 32^{11}=\left(2^5\right)^{11}=2^{55}\)
\(17^{14}>16^{14}=\left(2^4\right)^{14}=2^{56}\)
\(\Rightarrow17^{14}>2^{56}>2^{55}>31^{11}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(31^{11}<32^{11}=\left(2^5\right)^{11}=16^{11}<16^{14}<17^{14}\)
Vậy \(31^{11}<17^{14}\).
![](https://rs.olm.vn/images/avt/0.png?1311)
3111 và 1714
3111<3211=(25)11=255
=>3111<255
1714>1614=(24)14=256
=>1714>256
=>3111<255<256<1714
=>3111<1714
\(31^{11}< 32^{11}=\left(2^5\right)^{11}=2^{55}< 2^{56}=\left(2^4\right)^{14}=16^{14}< 17^{14}\)
\(=>31^{11}< 17^{14}\)
Vậy........
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có:
3111 < 3211 = (25)11 = 255
1714 > 1614 = (24)14 = 256
Vì 255 < 256 => 3211 < 1614 => 3111 < 1714
Ta có : \(31^{11}< 32^{11}=\left(2^5\right)^{11}=2^{55}\)
\(\Rightarrow31^{11}< 2^{55}\)
\(17^{14}>16^{14}=\left(2^4\right)^{14}=2^{56}\)
\(\Rightarrow17^{14}>2^{56}\)
\(\Rightarrow31^{11}< 2^{55}< 2^{56}< 17^{14}\)
\(\Rightarrow31^{11}< 17^{14}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Vì (-17)14<0(Vì có -17)
3111>0(vì hai số 31;11 là số nguyên dương)
Suy ra:3111>(-17)14
Ta có: 174 < 1711
1711<3111
=> 174<3111