so sánh
a=2016.2017-1/2016.2017
b=2017.2018-1/2017.2018
A=\(\frac{2016.2017+1}{2016.2017}\)
B=\(\frac{2017.2018+1}{2017.2018}\)
So sánh A và B
xet bt A ta co
A=2016.2017+1/2016.2017
=1+1/2016.2017
xet bt B ta co
B=2017.2018+1/2017.2018
=1+1/2017.2018
vì 1/2016.2017>1/2017.2018
nen 1+1/2016.2017>1+1/2017.2018
suy ra A>B
ai thay mik lam đúng thì k cho mik nha
Ta có:
\(A=\frac{2016.2017+1}{2016.2017}=\frac{2016.2017}{2016.2017}+\frac{1}{2016.2017}=1+\frac{1}{2016.2017}\)
\(B=\frac{2017.2018+1}{2017.2018}=\frac{2017.2018}{2017.2018}+\frac{1}{2017.2018}=1+\frac{1}{2017.2018}\)
So sánh:
\(A=\frac{1}{2016.2017}+1\)và \(B=\frac{1}{2017.2018}+1\)
Vì A và B đều cộng cho 1 nên tiêu giảm
=> \(A=\frac{1}{2016.2017}\)và \(B=\frac{1}{2017.2018}\)
Ta thấy:
Phần tử đã bằng nhau nên ta so sánh phần mẫu.
Ta thấy : 2016.2017 < 2017.2018
=>\(\frac{1}{2016.2017}>\frac{1}{2017.2018}\)
=> A > B
So sánh : A=\(\dfrac{2016.2017+1}{2016.2017}\) và B=\(\dfrac{2017.2018+1}{2017.2018}\) . Và giải thích giúp mình sao lại ra đáp án như vậy !!
A=\(\dfrac{2016.2017+1}{2016.2017}=\dfrac{2016.2017}{2016.2017}+\dfrac{1}{2016.2017}=1+\dfrac{1}{2016.2017}\)
A=\(\dfrac{2017.2018+1}{2017.2018}=\dfrac{2017.2018}{2017.2018}+\dfrac{1}{2017.2018}=1+\dfrac{1}{2017.2018}\)
Mà 1=1; \(\dfrac{1}{2016.2017}\)>\(\dfrac{1}{2017.2018}\) nên A>B
So sánh : 2017.2018 - 1 / 2017.2018 và 2018.2019 - 1 / 2018 . 2019
\(\frac{2017.2018-1}{2017.2018}=1-\frac{1}{2017.2018}\)
\(\frac{2018.2019-1}{2018.2019}=1-\frac{1}{2018.2019}\)
Ta thấy \(2017.2018< 2018.2019\)
nên \(\frac{1}{2017.1018}>\frac{1}{2018.2019}\)
\(\Rightarrow\)\(1-\frac{1}{2017.2018}< 1-\frac{1}{2018.2019}\)
Vậy \(\frac{2017.2018-1}{2017.2018}< \frac{2018.2019-1}{2018.2019}\)
So sánh
\(\frac{2017.2018+1}{2017.2018}\) và \(\frac{2018.2019+1}{2018.2019}\)
\(\frac{2017.2018}{2017.2018-1}\) và \(\frac{2018.2019}{2018.2019-1}\)
555555555555500000000000000.................
Ta có : \(\frac{2017.2018+1}{2017.2018}=1+\frac{1}{2017.2018}\)
\(\frac{2018.2019+1}{2018.2019}=1+\frac{1}{2018.2019}\)
Mà : \(\frac{1}{2017.2018}>\frac{1}{2018.2019}\) => \(\frac{2017.2018+1}{2017.2018}>\frac{2018.2019+1}{2018.2019}\)
So sánh
a) \(\frac{53}{57}\)và \(\frac{531}{571}\)
b) \(\frac{2018.2019-1}{2018.2019}\) và \(\frac{2017.2018-1}{2017.2018}\)
a) \(\frac{53}{57}=\frac{530}{570}\)
Ta có : 1 - \(\frac{530}{570}\)= \(\frac{40}{570}\) ; 1 - \(\frac{531}{571}=\frac{40}{571}\)
Vì \(\frac{40}{570}>\frac{40}{571}\) nên \(\frac{53}{57}< \frac{531}{571}\)
So sánh
C=2017.2018-1/2017.2018 và D=2018.2019-1/2018.2019
Ta có:
\(C=\frac{2017.2018-1}{2017.2018}=1-\frac{1}{2017.2018}\)
\(D=\frac{2018.2019-1}{2018.2019}=1-\frac{1}{2018.2019}\)
Mà ta có:
\(\frac{1}{2017.2018}>\frac{1}{2018.2019}\Rightarrow1-\frac{1}{2017.2018}< 1-\frac{1}{2018.2019}\Rightarrow C< D\)
1.22+2.32+3.42+...+2016.20172+2017.20182
Cho A=1/1.2+1/3.4+....+1/2017.2018
B=1/1010+1/1011+......+1/2018
So sánh A và B
Tìm x
\(\frac{x-2017}{2015.2016}+\frac{x-2018}{2016.2017}+\frac{x-2019}{2017.2018}+\frac{x-2020}{2018.1019}=\frac{1}{2015}+\frac{1}{2016}+\frac{1}{2017}+\frac{1}{1018}\)