Ta có :A = 1+ 2+.......+10/1+2+3+.......+10 suy ra : A = 55/55 = 1 B tương tự = 55/55 = 1 vậy A = B
Ta có :A = 1+ 2+.......+10/1+2+3+.......+10 suy ra : A = 55/55 = 1 B tương tự = 55/55 = 1 vậy A = B
a)Chứng minh \(\dfrac{1}{2}< \dfrac{1}{51}+\dfrac{1}{52}+\dfrac{1}{53}+..........+\dfrac{1}{100}< 1\)
b)So sánh A=\(\dfrac{10^{19}+1}{10^{20}+1}\) B=\(\dfrac{10^{20}+1}{10^{21}+1}\)
so sanh \(A=\dfrac{10^{10}+1}{10^{10}-1}\)
\(B=\dfrac{10^{10}-1}{10^{10}-3}\)
So sánh 2 biểu thức
\(A=\dfrac{10^{10}+1}{10^{10}-1}\) \(B=\dfrac{10^{10}-1}{10^{10}-3}\)
So sánh A = \(\dfrac{10^{11}-1}{10^{12}-1}\) và B =\(\dfrac{10^{10}+1}{10^{11}+1}\)
So sánh:
A = \(\dfrac{10^{1990}+1}{10^{1991}+1}\)
B = \(\dfrac{10^{1991}+1}{10^{1992}+1}\)
So sánh A và B :
a) \(A=\dfrac{20}{39}+\dfrac{22}{27}+\dfrac{18}{43}\)
\(B=\dfrac{14}{39}+\dfrac{22}{29}+\dfrac{18}{41}\)
b) \(A=\dfrac{3}{8^3}+\dfrac{7}{8^4}\)
\(B=\dfrac{7}{8^3}+\dfrac{3}{8^4}\)
c) \(A=\dfrac{10^7+5}{10^7-8}\)
\(B=\dfrac{10^8+6}{10^8-7}\)
d) \(A=\dfrac{10^{1992}+1}{10^{1991}+1}\)
\(B=\dfrac{10^{1993}+1}{10^{1992}+1}\)
So sánh 2 biểu thức A và B biết:
A=\(\dfrac{10^{2007}+1}{10^{2008}+1}\)
B=\(\dfrac{10^{2008}+1}{10^{2009}+1}\)
So sánh:
A = \(\dfrac{20^{10}+1}{20^{10}-1}\)
B = \(\dfrac{20^{10}-1}{20^{10}-3}\)