SO SÁNH:A=\(\frac{10^8+2}{10^8-1}\)
B=:\(\frac{10^8}{10^8-3}\)
So sánh:A=\(\frac{^{10^8}+2}{10^8-1}\)
Và B=\(\frac{10^8}{10^8-3}\)
Vi 10^8/10^8-3 > 1 => 10^8/10^8-3 > 10^8+2/10^8+2-3=10^8+2/10^8-1
=>10^8/10^8-3>10^8+2/10^8-1
so sánh:A =10^8 + 2/ 10^8 -1 : B =10^8/ 10^8 -3
mình đang cần gấp lắm giúp mình nha các bạn
A>1
B<1
bvaif này dễ lần sau sẽ có bài khó hơn là nó ko CMR đc a lớn hơn hay bé hơn 1
So sánh:
a/ \(A=\dfrac{17^{18}+1}{17^{19}+1};B=\dfrac{17^{17}+1}{17^{18}+1}\)
b/ \(A=\dfrac{10^8-2}{10^8+2};B=\dfrac{10^8}{10^8+4}\)
c/ \(A=\dfrac{20^{10}+1}{20^{10}-1};B=\dfrac{20^{10}-1}{20^{10}-3}\)
GIÚP MÌNH VỚI
Giải:
a) A=1718+1/1719+1
17A=1719+17/1719+1
17A=1719+1+16/1719+1
17A=1+16/1719+1
Tương tự:
B=1717+1/1718+1
17B=1718+17/1718+1
17B=1718+1+16/1718+1
17B=1+16/1718+1
Vì 16/1719+1<16/1718+1 nên 17A<17B
⇒A<B
b) A=108-2/108+2
A=108+2-4/108+2
A=1+-4/108+2
Tương tự:
B=108/108+4
B=108+4-4/108+1
B=1+-4/108+1
Vì -4/108+2>-4/108+1 nên A>B
c)A=2010+1/2010-1
A=2010-1+2/2010-1
A=1+2/2010-1
Tương tự:
B=2010-1/2010-3
B=2010-3+2/2010-3
B=1+2/2010-3
Vì 2/2010-3>2/2010-1 nên B>A
⇒A<B
Chúc bạn học tốt!
1,So sánh:A=108+2/108-1 và B=108/108-3
2,So sánh :A=108+2 và B=108/108-3
so sánh
a, \(a=\frac{10^{11}-1}{10^{12}-1}\&b=\frac{10^{10}+1}{10^{11}+1}\)
b,\(a=\frac{10^8+2}{10^8-1}\&b=\frac{10^8}{10^3-3}\)
So sánh \(A=\frac{10^8+2}{10^8-1}\)\(B=\frac{10^8}{10^8-3}\)
\(A=\frac{10^8+2}{10^8-1}=\frac{\left(10^8-1\right)+3}{10^8-1}=\frac{10^8-1}{10^8-1}+\frac{3}{10^8-1}=1+\frac{3}{10^8-1}\)
\(B=\frac{10^8}{10^8-3}=\frac{\left(10^8-3\right)+3}{10^8-3}=\frac{10^8-3}{10^8-3}+\frac{3}{10^8-3}=1+\frac{3}{10^8-3}\)
Vì \(1+\frac{3}{10^8-1}<1+\frac{3}{10^8-3}\) nên A < B
Ta có :
A = 108 + 2 / 10 8 - 1 = 1 + 3 / 10 8 - 1
B = 108 / 10 8 - 3 = 1 + 3 / 108 - 3
Vì 3/ 108 - 1 < 3 / 108 - 3=> A < B
A = \(\dfrac{10^8+2}{10^8-1}\) = \(\dfrac{\left(10^8-1\right)+3}{10^8-1}\) = \(\dfrac{10^8-1}{10^8-1}\) + \(\dfrac{3}{10^8-1}\) = 1+ \(\dfrac{3}{10^8-1}\)
B = \(\dfrac{10^8}{10^8-3}\) = \(\dfrac{\left(10^8-3\right)+3}{10^8-3}\) = \(\dfrac{10^8-3}{10^8-3}\) +\(\dfrac{3}{10^8-3}\)= 1+ \(\dfrac{3}{10^8-3}\)
Vì 1 +\(\dfrac{3}{10^8-1}\) < 1 + \(\dfrac{3}{10^8-3}\) nên A < B
\(\dfrac{3}{10^8-3}\)\(\dfrac{3}{10^8-3}\)
Cho \(A=\frac{10^8+2}{10^8-1};B=\frac{10^8}{10^8-3}\)so sánh A với B
So sánh \(A=\frac{10^8+2}{10^8+1};B=\frac{10^8}{10^8-3}\)
\(A=\frac{10^8+2}{10^8+1}=1+\frac{1}{10^8+1}
\(10^8=a\)
\(A-B=\frac{a+2}{a+1}-\frac{a}{a-3}=\frac{\left(a+2\right)\left(a-3\right)-a\left(a+1\right)}{\left(a+1\right)\left(a-3\right)}=\frac{-2a-6}{\left(a+1\right)\left(a-3\right)}
so sánh \(A=\frac{10^2+2}{10^8-1};B=\frac{10^8}{10^8-3}\)