1/so sanh cac so sau :
a/ 714 va 507 b/530 va 12410
c/ 921 va 7297 d/3111 va 1714
1 .so sanh cac phan so sau day :
2014/2013 va 2015/2014
530/570 va 531/571
2 . a/b sau khi rut gon duoc c/d nguoi ta chung to rang :
a/b=a+c/b+d
So sanh cac so sau day 1 cach nhanh chong
A/ 3/4 va 115/14
B/ 2000/1999 a 1998//1999
C/ -17/234 va 1/1995
D/ 23/-15 va -17/-49
a) 3/4 < 1
115/14 > 1
=> 3/4 < 115/14
b) 2000/1999 > 1
1998/1999 < 1
=> 2000/1999>1998/1999
c)-17/234 < 0 , 1/1995 > 0
=> -17/234 < 1/1995
d) 23/-15 < 0 ; -17/-49>0
=> 23/-15 < -17/-49
So sanh cac phan so sau
a) -403/407 va -813/817
b)-251/318 va -317/171
1)so sanh cac so sau:
a)5^40 va 620^10
b)333^444 va 444^333
Bai 2 : so sanh cac phan so sau ;
a,1/2;1/3;2/3 b, 4/9;-1/2;3/7 c, 27/82 va 26/75 d, -49/78 va 64/-95
a) Ta có:
+) \(\dfrac{1}{2}=\dfrac{3}{6}\)
+) \(\dfrac{1}{3}=\dfrac{2}{6}\)
+) \(\dfrac{2}{3}=\dfrac{4}{6}\)
=> \(\dfrac{2}{6}< \dfrac{3}{6}< \dfrac{4}{6}\)
hay \(\dfrac{1}{3}< \dfrac{1}{2}< \dfrac{2}{3}\)
b) Ta có:
+) \(\dfrac{4}{9}=\dfrac{56}{126}\)
+) \(-\dfrac{1}{2}=-\dfrac{63}{126}\)
+) \(\dfrac{3}{7}=\dfrac{54}{126}\)
=> \(-\dfrac{63}{126}< \dfrac{54}{126}< \dfrac{56}{126}\)
hay \(-\dfrac{1}{2}< \dfrac{3}{7}< \dfrac{4}{9}\)
c) Ta có:
+) \(\dfrac{27}{82}=\dfrac{2025}{6150}\)
+) \(\dfrac{26}{75}=\dfrac{2132}{6150}\)
=> \(\dfrac{2025}{6150}< \dfrac{2132}{6150}\)
hay \(\dfrac{27}{82}< \dfrac{26}{75}\)
d) Ta có:
+) \(-\dfrac{49}{78}=-\dfrac{4655}{7410}\)
+) \(-\dfrac{64}{95}=-\dfrac{4992}{7410}\)
=> \(-\dfrac{4665}{7410}>-\dfrac{4992}{7410}\)
hay \(-\dfrac{49}{78}>-\dfrac{64}{95}\)
So sanh cac so sau bang hai cach :
a, 2^50 va 16^20
b,2^30 va 3^20
c, 2^20 va 2 ^16.15
d, 33^44 va 44^33 ( 1 cach )
e,72^45 - 72^44 va 72^44 - 72^43
so sanh cac phan so sau;
a, 3/4 va 4/5
b, 7/12 va 17/36
c, 5/6 va 6/7 va 7/8
a, Ta có : 1 - 3/4 = 1/4 ; 1 - 4/5 = 1/5
Vì 1/4 > 1/5 nên 3/4 < 4/5
b, Ta có :7/12 = 21/36
Vì 21/36 > 17/36 nên 7/12 > 17/36
c, Ta có:
1 - 5/6 = 1/6
1 - 6/7 = 1/7
1 - 7/8 = 1/8
Vì 1/6 > 1/7 > 1/8 nên 5/6 < 6/7 < 7/8
So sanh :
a, 9 mu 5 va 27 mu 3
b, 3 mu 200 va 2 mu 300
c, 31 mu 11 va 17 mu 14
d, 199 mu 20 va 2003 mu 15
e, 2 mu 1993 va 7 mu 714
a, 9^5>27^3
b,3^200>2^300
c, 32^11<17^14
So sanh cac so sau :
a,10^30 va 2^100
b, 3^450 va 5^300
c, 333^444 va 444^333
U cam on ban nhe .
Ban giup minh tra loi voi
Cho 2 phan so a/b va c/d (a,b,c,d€z,b,d be hon 0)
a) Chung minh rang a/b be hon c/d va nguoc lai.
b) Ap dung ket qua tren de so sanh cac phan so sau:
11/13 va 22/27; -5/11 va -9/37; -7/15 va -19/29