so sanh A= 13^15 + 1/13^6 +1 va B= 13^16 + 1/13^ 7+1
So sanh 2 phan so
a, 2013 / 2018 va 2012 / 2008
b. 2013 / 2008 va 2008 / 2003
c . 24 /47 va 13 / 27
d. 37/ 23 va 42 / 22
e.1 / 2 va 1 / 2017
g. 12 / 13 va 6 / 7
a, 2013/2018 < 2012/2018
b, 2013/2008 < 2008/2003
c,24/47 > 13/27
d,37/23 < 42/22
e 1/2 > 1/2017
g, 12/13 > 6/7
A=\(\dfrac{13^{15}+1}{13^{16}+1}\) và B= \(\dfrac{13^{16}+1}{13^{17}+1}\)
so sánh A và B
\(ta có A=\dfrac{13^{15}+1}{13^{16}+1}=\dfrac{13^{15}}{13^{16}}+1\)=\(\dfrac{1}{13}+1\)
B=\(\dfrac{13^{16}+1}{13^{17}+1}=\dfrac{13^{16}}{13^{17}}+1\)=\(\dfrac{1}{13}+1\)
vậy A=B
\(A=\dfrac{13^{15}+1}{13^{16}+1}vàB=\dfrac{13^{16}+1}{13^{17}+1}\)
ta có
\(\dfrac{13^{16}+1}{13^{17}+1}< 1\Rightarrow\dfrac{13^{16}+1+12}{13^{17}+1+12}=\dfrac{13\left(13^{15}+1\right)}{13\left(13^{16}+1\right)}=\dfrac{13^{15}+1}{13^{16}+1}=A\)
vậy B<A
\(A=\dfrac{13^{15}+1}{13^{16}+1}vàB=\dfrac{13^{16}+1}{13^{17}+1}\)
ta có B<1 nên
\(\dfrac{13^{16}+1}{13^{17}+1}< \dfrac{13^{16}+1+12}{13^{17}+1+12}=\dfrac{13\left(13^{15}+1\right)}{13\left(13^{16}+1\right)}=\dfrac{13^{15}+1}{13^{16}+1}=A\)
Vậy B<A
1) tim x biết:
a) (19.x +2.5^2) : 14=(13-8)^2 - 4^2
b) 2.3^x=10.3^12+8.27^4
2) so sanh
a) 5^23 va 6.5^22
b)21^15 va 27^5.49^8
c)3^39 va 11^21
d) 7.2^13 va 2^16
1 a, 3 va 1/5 - 2 va 1/6 + 1/5
b, 5 va 12/13 - 2 va 15/26 + 1/26
c, 7 va 1/12 + 1/12 - 6 va 1/4
2 tinh gia tri bieu thuc
a, 3 va 2/9 - [1 va 5/8 + 1 va 2/9 ] - 3/8
b, 4 va 2/5 - 1 va 3/7 - 1 va 4/7 + 1/5
c, 1 va 9/12 - 5/4 - 1/2
3 tinh
a, 6 nhan 7 nhan 8 nhan 9 nhan 1 tren 18 nhan 16 nhan 14 nhan 12 nhan 2
b, 4 nhan 15 nhan 9 nhan 24 tren 3 nhan 12 nhan 8 nhan 5
4 rut gon cac phan so
a, 96/150 ; 255/408 ; 630/224
b, 1515/1717; 352352/470470; 200620062006/200520052005
5 so sanh cac phan so
a, 7/9 va 9/7 ; b, 135/120 va 13/8; c, 3535/4848 va 5/8 ; d, 650650/480480 va 222222/144144
6, so sanh hai phan so
a, 2005/2006 va 2006/2007 ; b, 2008/2007 va 2007/2006
cac ban lam tung buoc nha
cho a= 1+3+3^2+...+3^12 / 1+3+3^2+...+3^13 va b = 1+5+5^2+5^3+...+5^12 / 1+5+5^2+...+5^13 so sanh a va b
Cho S = 1/11 + 1/12 + 1/13 + 1/14 + 1/15 + 1/16 + 1/17 + 1/18 + 1/19 + 1/20.
Hay so sanh S va 1/2
1so sanh cac phan so sau
a,2/3 va -1/4
b -7/10 va 7/-8
c 6/7 va 3/5
d -14/21 va 60/-72
e 16/9 va24/13
g 27/82 va 26/75
so sánh A và B biết A= 1315 +1/ 1316+1; B=1316+1/ 1317+1
SO SÁNH A VÀ B
A= 13^16 + 1/13^17+1 VÀ B=13^15 +1 /13^16+1
A=1999^2000 +1 / 1999^1999 +1 VÀ B=1999^1999+1/1999^1998 +1