Lời giải:
a.
\(A-B=\frac{7-3}{84}-\frac{7-3}{83}=\frac{4}{84}-\frac{4}{83}<0\\ \Rightarrow A< B\)
b.
\(A-1=\frac{13}{10^7-8}\\ B-1=\frac{13}{10^8-7}\)
Hiển nhiên $10^7-8< 10^8-7$
$\Rightarrow \frac{13}{10^7-8}> \frac{13}{10^8-7}$
$\Rightarrow A-1> B-1\Rightarrow A> B$
so sánh A và B :
a) A = \(\frac{20}{39}+\frac{22}{27}+\frac{18}{43}\) ; B = \(\frac{14}{39}+\frac{22}{29}+\frac{18}{41}\)
b) A = \(\frac{3}{8^3}+\frac{7}{8^4}\) , B= \(\frac{7}{8^3}+\frac{3}{8^4}\)
c) A = \(\frac{10^7+5}{10^7-8}\) , B = \(\frac{10^8+6}{10^8-7}\)
d) A = \(\frac{10^{1992}+1}{10^{1991}+1}\), B = \(\frac{10^{1933}+1}{10^{1992}+1}\)
So sánh A và B:
a)A=\(\frac{10^7+5}{10^7-8}\); B=\(\frac{10^8+6}{10^8-7}\)
bài 1 So sánh
a)\(A=\frac{3}{8^3}+\frac{7}{8^4}\) ; \(B=\frac{7}{8^3}+\frac{3}{8^4}\)
b)\(A=\frac{10^{1992}+1}{10^{1991}+1};B=\frac{10^{1993}+1}{10^{1992}+1}\)
c)\(A=\frac{10^7+5}{10^4-8};B=\frac{10^8+6}{10^8-7}\)
d)\(A=\frac{1+5+5^2+...+5^9}{1+5+5^2+...+5^8};B=\frac{1+3+3^2+...+3^9}{1+3+3^2+...+3^8}\)
e)\(A=\frac{2011}{2012}+\frac{2012}{2013};B=\frac{2011+2012}{2012+2013}\)
1. So Sánh: \(A=\frac{10^7+5}{10^7-8};B=\frac{10^8+6}{10^8-7}\)
So sánh A và B biết:
a) A =\(\frac{10^7+5}{10^7-8}\) B =\(\frac{10^8+6}{10^8-7}\)
B) A =\(\frac{15^{16}-13}{15^{16}+7}\) B = \(\frac{16^{17}-12}{16^{17}+8}\)
so sánh Avà B :
a)A=\(\frac{n}{n+1}\);B=\(\frac{n+2}{n+3}\)
b)A=\(\frac{n}{2n+1}\);B=\(\frac{3n+1}{6n+3}\)
c)A=\(\frac{10^7+5}{10^7-8}\);B=\(\frac{10^8+6}{10^8-7}\)
d)A=\(\frac{10^{1992}+1}{10^{1991}+1}\);B=\(\frac{10^{1993}+1}{10^{1992}+1}\)
so sánh A và B
\(A=\frac{10^7+5}{10^7-8}\) và \(B=\frac{10^5+6}{10^5-7}\)
So sánh A=\(\frac{10^7+8}{10^7-8}\)B=\(\frac{10^8+8}{10^7-8}\)
Sso sánh A và B:
A= \(\frac{10^7+5}{10^7-8}\)
B = \(\frac{10^8+6}{10^8-7}\)
Nhanh nha,10 giờ 30 phải nộp mik rồi
