So sánh:
a ) 25 26 v à 50 51 ; b ) 213 321 v à 105 213 ;
c ) − 99 100 v à − 21 22 ; d ) − 124 129 v à − 132 137
25/26 và 50/51 ; 149/157 và 449/457 ; 13/79 và 34/204 ; 25/103 và 74/295 ; 58/83 và 36/55 so sánh phân số
a: \(\dfrac{25}{26}=1-\dfrac{1}{26}\)
\(\dfrac{50}{51}=1-\dfrac{1}{51}\)
mà \(-\dfrac{1}{26}< -\dfrac{1}{51}\)
nên \(\dfrac{25}{26}< \dfrac{50}{51}\)
b: \(\dfrac{149}{157}=1-\dfrac{8}{157}\)
\(\dfrac{449}{457}=1-\dfrac{8}{457}\)
mà \(-\dfrac{8}{157}>-\dfrac{8}{457}\)
nên \(\dfrac{149}{157}>\dfrac{449}{457}\)
So sánh phân số
a) 25/26 và 50/52
b)51/58 và 61/68
c)101/506 và 707/3534
a) \(\frac{25}{26}=\frac{50}{52}\) b) \(\frac{51}{58}< \frac{61}{68}\) c) \(\frac{101}{506}< \frac{707}{3534}\)
So sánh
\(a,2^{30}+3^{30}+4^{30}v\text{à}3^{20}+6^{20}+8^{20}\)
\(b,2^{30}+3^{30}+4^{30}v\text{à}3.24^{10}\)
\(c,2^0+2^1+2^2+...+2^{50}v\text{à}2^{51}\)
c) Đặt \(A=2^0+2^1+2^2+...+2^{50}\)
\(\Leftrightarrow2A=2^1+2^2+2^3...+2^{51}\)
\(\Leftrightarrow2A-A=2^1+2^2+2^3...+2^{51}\)\(-2^0-2^1-2^2-...-2^{50}\)
\(\Leftrightarrow A=2^{51}-2^0=2^{51}-1< 2^{51}\)
Vậy \(2^0+2^1+2^2+...+2^{50}< 2^{51}\)
a)Ta có: \(\hept{\begin{cases}2^{30}=\left(2^3\right)^{10}=8^{10}\\3^{30}=\left(3^3\right)^{10}=27^{10}\\4^{30}=\left(2^2\right)^{30}=2^{60}\end{cases}}\)và \(\hept{\begin{cases}3^{20}=\left(3^2\right)^{10}=9^{10}\\6^{20}=\left(6^2\right)^{10}=36^{10}\\8^{20}=\left(2^3\right)^{20}=2^{60}\end{cases}}\)
Mà \(8^{10}< 9^{10}\); \(27^{10}< 36^{10}\);\(2^{60}=2^{60}\)nên
\(8^{10}+27^{10}+2^{60}< 9^{10}+36^{10}+2^{60}\)
hay \(2^{30}+3^{30}+4^{30}< 3^{20}+6^{20}+8^{20}\)
b) Ta có: \(4^{30}=2^{30}.2^{30}=8^{10}.4^{15}\)
\(3.24^{10}=3.8^{10}.3^{10}=3^{11}.8^{10}\)
Vì \(4^{15}>3^{11}\) nên \(8^{10}.4^{15}>3^{11}.8^{10}\)
hay \(2^{30}+3^{30}+4^{30}>3.24^{10}\)
So sánh:
a)\(3^{200}v\text{à}2^{300}\)
b) \(71^{50}v\text{à}37^{75}\)
c) \(\frac{2016014}{2017015}v\text{à}\frac{2016016014}{2017017015}\)
a) 3200=(32)100=9100 ; 2300=(23)100=8100
=> 9100>8100 hay 3200>2300
b) 7150=(712)25=504125 ; 3775=(373)25=5065325
=> 504125<5065325 hay 7150<3775
c)rút gọn
2016014/2017015=2014/2015
2016016014/2017017015=2014/2015
=> 2014/2015 = 2014/2015
27/26 ; 25/24 ; 26/25 ; 18/17 ; 4/3 ; 51/50 sếp theo thứ tự tăng dần
\(\dfrac{51}{50};\dfrac{27}{26};\dfrac{25}{24};\dfrac{18}{17};\dfrac{4}{3}\)
\(\dfrac{51}{50}< \dfrac{27}{26}< \dfrac{25}{24}< \dfrac{26}{25}< \dfrac{18}{17}< \dfrac{4}{3}\)
So sánh các số sau:
a) \(0,5\sqrt{100}-\sqrt{\frac{4}{25}}v\text{à}\left(\sqrt{1\frac{1}{9}}-\sqrt{\frac{9}{16}}\right):5\)
b) \(\sqrt{25+9}v\text{à}\sqrt{25}+\sqrt{9}\)
\(\frac{25}{48}v\text{à}\frac{34}{69};\frac{62}{139}v\text{à}\frac{57}{141}\)So sánh phân số
help me now!!!!!
\(\Leftrightarrow\frac{25}{48}.2=\frac{34}{69}.2\)
\(\Leftrightarrow\frac{25}{24}\text{và}\frac{68}{69}\)
mà\(\frac{25}{24}>1\)
\(\frac{68}{69}< 1\)
\(\Rightarrow\frac{25}{24}>\frac{68}{69}\)
\(\Rightarrow\frac{25}{48}>\frac{34}{69}\)
So sánh các số hữu tỉ:
a) \(\frac{-17}{24}v\text{à}\frac{-25}{31}\)
b) \(\frac{-27}{38}v\text{à}\frac{-125}{195}\)
c) \(\frac{-22}{111}v\text{à}\frac{-27}{134}\)
a)-17/24 > -25/31
b)-27/38 < -125/195
c)-22/111> -27/134
nhớ k nha!!!!!!!!!!!!!!!!!!
So sánh: \(\frac{27}{39}v\text{à}\frac{26}{41}\)
Trình bày cách làm cho mình nha
lấy phân số trung gian
có \(\frac{27}{39}>\frac{27}{41}\) (1)
\(\frac{26}{41}\frac{27}{41}>\frac{26}{41}\) hay \(\frac{27}{39}>\frac{26}{41}\)
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**** cho mình nha bnKhánh Linh