so sánh với 1
\(\frac{2014x2015-2}{2013x2015+2012}\)
So sánh:
A = \(\frac{2014x2015-1}{2014x2015}\) B = \(\frac{2015x2016-1}{2015x2016}\)
\(A=1-\frac{1}{2014x2015}\)
\(B=1-\frac{1}{2015x2016}\)
\(2014x2015< 2015x2016\Rightarrow\frac{1}{2014x2015}>\frac{1}{2015x2016}\Rightarrow A< B\)
2014x2015-1/2014x2015 và 2015x2016-1/2015x2016
2014x2015-1/2014x2015=2014x2015/2014x2015-1/2014x2015=1-1/2014x2015
2015x2016-1/2015x2016=2015x2016/2015x2016-1/2015x2016=1-1/2015x2016
=>1-1/2015x2016>1-1/2014x2015
=>2015x2016-1/2015x2016>2014x2015-1/2014x2015
So sánh: \(\frac{2012}{\sqrt{1}}+\frac{2012}{\sqrt{2}}+....+\frac{2012}{\sqrt{2025}}\) với \(30180\)
So sánh P và Q biết : P = 2010/2011 + 2011/2012 + 2012/2013 và Q = 2010+2011+2012/ 2011 +2012+2013
Chứng tỏ N < 1 với N = \(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{2009^2}+\frac{1}{2010^2}\)
Ta có: \(\frac{1}{2^2}+\frac{1}{3^2}+...+\frac{1}{2010^2}
\(\frac{2012^{2010}+1}{2012^{2011}+1}và\frac{2012^{2011}+1}{2012^{2012}+1}\)so sánh 2 số
So sánh phân thức A=\(\frac{2013^2-2012^2}{2013^2+2012^2}\) với B=\(\frac{2013-2012}{2013+2012}\)
\(\frac{2012+2013x2014}{2014x2015+2016}\)
nhanh mình cần gấp
1 tick ngay
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
Cho U = \(\frac{1}{1!}+\frac{1}{2!}+\frac{1}{3!}+...+\frac{1}{2012!}\)
So sánh U với 2
đặt B=1/2.3+1/3.4+...+1/2011.2012
ta có U =1+1/1.2+1/1.2.3+...+1/1.2.3....2012
B=1/1.2+1/2.3+1/3.4+...+1/2011.2012
=1-1/2+1/2-1/3+...+1/2011-1/2012
=1-1/2012<1 (1)
Mà 1<2(2)
A =1+1/1+1/1.2+1/1.2.3+...+1/1.2.3...2012<1-1/2+1/2-1/3+...+1/2011-1/2012 (3)
từ (1),(2),(3) =>U<2
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 !