Câu 1 So sánh
M= 1919*171717/ 191919*1717 và N= 18/19
M= -1/1001+-1/1002+-1/1003+...+-1/2000 với N=-7/2
M=13579/34567 và B= 13580/34569
A=5^12+1/5^13+1 và B=5^11+1/5^12+1
A=100^100+1/100^99+1 và B=100^99+1/100^98+1
A==(1/80)^7 và B=(1/243)^6
A=-(3/8)^5 và B=(5/243)^3
Các bn giúp mk nhé
mk cảm ơn nhìu lém lun
M=\(\dfrac{1919\times171717}{191919\times1717}\) và N=\(\dfrac{18}{19}\)
Ta có :
M= \(\dfrac{1919\times171717}{191919\times1717}\)
M=\(\dfrac{19\times17}{19\times17}\)
M= 1
Mà N= \(\dfrac{18}{19}\)
Vì: 1>\(\dfrac{18}{19}\)
\(\Rightarrow\)\(\dfrac{1919\times171717}{191919\times1717}\) > \(\dfrac{18}{19}\)
\(\Rightarrow\)M > N
A=\(\dfrac{5^{12}+1}{5^{13}+1}\) và B =\(\dfrac{5^{11}+1}{5^{12}+1}\)
Ta có:
A=\(\dfrac{5^{12}+1}{5^{13}+1}\)
\(\Rightarrow\)5.A=5.\(\dfrac{5^{12}+1}{5^{13}+1}\)
=\(\dfrac{5.\left(5^{12}+1\right)}{5^{13}+1}\)
=\(\dfrac{5^{13}+6}{5^{13}+1}\)
=\(\dfrac{\left(5^{13}+1\right)+6}{5^{13}+1}\)
=\(\dfrac{5^{13}+1}{5^{13}+1}\) + \(\dfrac{6}{5^{13}+1}\)
= 1 + \(\dfrac{6}{5^{13}+1}\)
B=\(\dfrac{5^{11}+1}{5^{12}+1}\)
\(\Rightarrow\)5.B = 5.\(\dfrac{5^{11}+1}{5^{12}+1}\)
=\(\dfrac{5.\left(5^{11}+1\right)}{5^{12}+1}\)
=\(\dfrac{5^{12}+6}{5^{12}+1}\)
=\(\dfrac{\left(5^{12}+1\right)+5}{5^{12}+1}\)
=\(\dfrac{5^{12}+1}{5^{12}+1}\) + \(\dfrac{5}{5^{12}+1}\)
= 1 + \(\dfrac{5}{5^{12}+1}\)
Vì: \(5^{13}+1\) > \(5^{12}+1\)
\(\Rightarrow\) \(\dfrac{5}{5^{13}+1}\) < \(\dfrac{5}{5^{12}+1}\)
\(\Rightarrow\) 1+\(\dfrac{5}{5^{13}+1}\) < 1+\(\dfrac{5}{5^{12}+1}\)
\(\Rightarrow\) 5.A < 5.B
\(\Rightarrow\) A < b
