so sánh:
\(A=\frac{2012^{37}+37^{2012}+1}{2012^{38}}\) và \(B=\frac{2012^{38}+37^{2012}+2}{2012^{39}}\)
so sánh:
\(A=\frac{2012^{37}+37^{2012}+1}{2012^{38}}\) và \(B=\frac{2012^{38}+37^{2012}+2}{2012^{39}}\)
So sánh \(A=\frac{2012^{37}+37^{2012}+1}{2012^{38}}\) với \(B=\frac{2012^{38}+37^{2012}+2}{2012^{39}}\)
giúp mình nha các bạn !
Toán lớp 6 (ban tổ chức đưng xóa câu hỏi của em vì online math đang bận mak em cần gấp nên sang đây hỏi)
So sánh
\(A=\frac{2012^{37}+37^{2012}+1}{2012^{38}}\)và \(B=\frac{2012^{38}+37^{2012}+2}{2012^{39}}\)
\(A=\frac{1}{2012}+\frac{37^{2012}}{2012^{38}}+\frac{1}{2012^{38}}\)
\(B=\frac{1}{2012}+\frac{37^{2012}}{2012^{39}}+\frac{2}{2012^{39}}\)
Ta có:
\(A-B=\frac{37^{2012}}{2012^{38}}-\frac{37^{2012}}{2012^{39}}+\frac{1}{2012^{38}}-\frac{2}{2012^{39}}\)
\(A-B=\frac{37^{2012}}{2012^{38}}\left(1-\frac{1}{2012}\right)+\frac{1}{2012^{38}}\left(1-\frac{2}{2012}\right)\)
\(A-B=\frac{37^{2012}}{2012^{38}}\left(\frac{2011}{2012}\right)+\frac{1}{2012^{38}}\left(\frac{2010}{2012}\right)\)
A - B > 0
=> A > B
A=201237/201238+ 372012/201238+1/201238
= 1/2012+ 372012/201238+ 1/201238
Tương tự ta có:
B=1/2012+ 372012/201239+1/201239+1/201239
Ta thấy: 1/2012=1/2012( ở 2 vế)
372012/201238 > 372012/ 201239( do cùng tử, mẫu nào nhỏ hơn thì phân số đó lớn hơn)
tương tự: 1/201238> 1/201239( 201238< 201239)
201239 là một số rất lớn nên 1/201239 rất bé và gần đến 0.
Vậy A>B.
Cho M= 2012^37+37^2012+1/2012^38 và N= 2012^38+37^2012+2/2012^39. So sánh M và N
Ta có :M=\(\frac{2012^{37}+37^{2012}+1}{2012^{38}}\)=\(\frac{1}{2012}\)+\(\frac{37^{2012}}{2018^{38}}\)+\(\frac{1}{2012^{38}}\)
N=\(\frac{2012^{38}+37^{2012}+2}{2012^{39}}\)=\(\frac{1}{2012}\)+\(\frac{37^{2012}}{2012^{39}}\)+\(\frac{2}{2012^{39}}\)
Suy ra: M-N=\(\frac{37^{2012}}{2012^{38}}\left(1-\frac{1}{2012}\right)\)+\(\frac{1}{2012^{38}}\left(1-\frac{2}{2012}\right)\)
\(\Rightarrow\)M-N=\(\frac{37^{2012}}{2012^{38}}.\frac{2011}{2012}+\frac{1}{2012^{38}}.\frac{2010}{2012}\)
\(\Rightarrow\)M-N>0
\(\Rightarrow\)M>N
Vậy M>N
So sánh \(\frac{37^{2013}+1}{37^{2012}+1}\) và\(\frac{37^{2014}+1}{37^{2013}+1}\)
Đặt \(A=\frac{37^{2013}+1}{37^{2012}+1}\) và \(B=\frac{37^{2014}+1}{37^{2013}+1}\) ta có :
\(\frac{1}{37}A=\frac{37^{2013}+1}{37^{2013}+37}=\frac{37^{2013}+37-36}{37^{2013}+37}=\frac{37^{2013}+37}{37^{2013}+37}-\frac{36}{37^{2013}+37}=1-\frac{36}{37^{2013}+37}\)
\(\frac{1}{37}B=\frac{37^{2014}+1}{37^{2014}+37}=\frac{37^{2014}+37-36}{37^{2014}+37}=\frac{37^{2014}+37}{37^{2014}+37}-\frac{36}{37^{2014}+37}=1-\frac{36}{37^{2014}+37}\)
Vì \(\frac{36}{37^{2013}+37}>\frac{36}{37^{2014}+37}\) nên \(1-\frac{36}{37^{2013}+37}< 1-\frac{36}{37^{2014}+37}\)
\(\Rightarrow\)\(\frac{1}{37}A< \frac{1}{38}B\)
\(\Rightarrow\)\(A< B\)
Vậy \(A< B\)
Chúc bạn học tốt ~
So sánh
a. 5\(^{37}\) và 11\(^{24}\)
b. \(\frac{a}{b}\) và \(\frac{a+2012}{b+2012}\)
a) Ta có:
537 > 536 = (53)12 = 12512
1124 = (112)12 = 12112
Vì 537 > 12512 > 12112
=> 537 > 1124
b) + Nếu a < b
=> 2012a < 2012b
=> 2012a + ab < 2012b + ab
=> a.(b + 2012) < b.(a + 2012)
=> \(\frac{a}{b}< \frac{a+2012}{b+2012}\)
+ Nếu a = b
=> 2012a = 2012b
=> 2012a + ab = 2012b + ab
=> a.(b + 2012) = b.(a + 2012)
=> \(\frac{a}{b}=\frac{a+2012}{b+2012}\)
+ Nếu a > b
=> 2012a > 2012b
=> 2012a + ab > 2012b + ab
=> a.(b + 2012) > b.(a + 2012)
=> \(\frac{a}{b}>\frac{a+2012}{b+2012}\)
So sánh 2 phân số :
\(A=\frac{2012^{2012}+1}{2012^{2013}+1}\) và \(B=\frac{2012^{2011}+1}{2012^{2012}+1}\)
ÁP DỤNG CÔNG THỨC NẾU \(\frac{a}{b}\)>1 thì
\(\frac{a}{b}\)>\(\frac{a+m}{b+m}\)
Ta có : \(\frac{2012^{12}+1}{2012^{13}+1}\)>\(\frac{2012^{12}+1+2011}{2012^{13}+1+2011}\)=\(\frac{2012^{12}+2012}{2012^{13}+2012}\)=\(\frac{2012.\left(2012^{11}+1\right)}{2012.\left(2012^{12}+1\right)}\)
rồi rút gọn thành \(\frac{2012^{11}+1}{2012^{12}+1}=B\)
Vậy A>B
Nhớ cho mình đúng nha
Ta có:\(A=\dfrac{2012^{2012}+1}{2012^{2013}+1}\)
\(\Rightarrow2012.A=\dfrac{2012^{2013}+2012}{2012^{2013}+1}=\dfrac{2012^{2013}+1+2011}{2012^{2013}+1}=1+\dfrac{2011}{2012^{2013}+1}\)Ta có:\(B=\dfrac{2012^{2011}+1}{2012^{2012}+1}\)
\(\Rightarrow2012.B=\dfrac{2012^{2012}+2012}{2012^{2012}+1}=\dfrac{2012^{2012}+1+2011}{2012^{2012}+1}=1+\dfrac{2011}{2012^{2012}+1}\)Vì\(\dfrac{2011}{2012^{2013}+1}< \dfrac{2011}{2012^{2012}+1}\)
\(\Rightarrow1+\dfrac{2011}{2012^{2013}+1}< 1+\dfrac{2011}{2012^{2012}+1}\)
\(\Rightarrow\dfrac{2012^{2012}+1}{2012^{2013}+1}< \dfrac{2012^{2011}+1}{2012^{2012}+1}\)
Vậy A<B
So sánh A và B biết : \(A=\frac{2012^{2012}+1}{2012^{2013}+1};B=\frac{2012^{2011}+1}{2012^{2012}+1}\)
\(10A=\frac{2012^{2013}+10}{2012^{2013}+1}=\frac{2012^{2013}+1+9}{2012^{2013}+1}=1+\frac{9}{2012^{2013}+1}\)
\(10B=\frac{2012^{2012}+10}{2012^{2012}+1}=\frac{2012^{2012}+1+9}{2012^{2012}+1}=1+\frac{9}{2012^{2012}+1}\)
Vì \(\frac{9}{2012^{2013}+1}
ta co A=\(\frac{2012^{2012}+1}{2012^{2013}+1}< \frac{2012^{2012}+1+2011}{2012^{2013}+1+2011}\)=\(\frac{2012^{2012}+2012}{2012^{2013}+2012}=\frac{2012\left(2012^{2011}+1\right)}{2012\left(2012^{2012}+1\right)}\)
=>A<B
a, CMR: Nếu 7x+4y chia hết cho 37 thì 13x+18y chia hết cho 37
b, So sánh: A= 2014^2012+1/2014^2013+1 và B= 2014^2011+1/2014^2012+1
a, Ta có : \(7x+4y⋮37\)
\(\Rightarrow23\left(7x+4y\right)⋮37\)
\(\Rightarrow161x+92y⋮37\)
\(\Rightarrow\left(13x+18y\right)+148x+74y⋮37\)
Mà \(\hept{\begin{cases}148x⋮37\\74x⋮37\end{cases}\Rightarrow13x+18y⋮37}\)
Vậy \(13x+18y⋮37\)
b, Ta có : \(A=\frac{2014^{2012}+1}{2014^{2013}+1}\)
\(\Rightarrow2014A=\frac{2014^{2013}+2014}{2014^{2013}+1}=\frac{2014^{2013}+1+2013}{2014^{2013}+1}=1+\frac{2013}{2014^{2013}+1}\)
Ta có : \(B=\frac{2014^{2011}+1}{2014^{2012}+1}\)
\(\Rightarrow2014B=\frac{2014^{2012}+2014}{2014^{2012}+1}=\frac{2014^{2012}+1+2013}{2014^{2012}+1}=1+\frac{2013}{2014^{2012}+1}\)
Vì \(2014^{2013}+1>2014^{2012}+1\)
\(\Rightarrow\frac{1}{2014^{2013}+1}< \frac{1}{2014^{2012}+1}\Rightarrow1+\frac{1}{2014^{2013}+1}< 1+\frac{1}{2014^{2012}+1}\)
\(\Rightarrow2014A< 2014B\Rightarrow A< B\)