So sanh
a) A = 2013. 2015 va B = 20142
b) A = 1030 va B = 2100
c) A = 333444 va B = 444333
d) A = 3450 va B = 5300
1. So sanh:
2014×2015-2/2013+2013×2014 voi 2014×2015-1/2014×2015
2. Cho a, b, c thuoc N* va a nho hon b.
Hay chung to: a/b nho hon a+c/b+c va 1 nho hon a/a+b +b/b+c+c/a+c
1 .so sanh cac phan so sau day :
2014/2013 va 2015/2014
530/570 va 531/571
2 . a/b sau khi rut gon duoc c/d nguoi ta chung to rang :
a/b=a+c/b+d
so sanh A va B biet :A=2011^2012-2011^2011 va b=2011^2013-2011^2012
A=99^2015+1/99^2014+1
B=99^2014+1/99^2013+1
so sanh a va b
A = 99^2015 + 1/99^2014 + 1 < 99^2015 + 1 + 98 / 99^2014 + 1 + 98
= 99^2015 + 99 / 99^2014 + 99
= 99(99^2014 + 1) / 99(99^2013+1)
= 99^2014 + 1 / 99^2013 + 1 = B
=> A < B
so sanh
a, \(\left|-2\right|^{300}\) va \(\left|-4\right|^{150}\)
b,\(\left|-2\right|^{300}\)va \(\left|-2\right|^{300}\)
co loi giai
a, Ta có:
\(\left|-2\right|^{300}=2^{300}\) (1)
\(\left|-4\right|^{150}=4^{150}=\left(2^2\right)^{150}=2^{300}\) (2)
Từ (1) và (2) \(\Rightarrow\) \(\left|-2\right|^{300}=\left|-4\right|^{150}\)
a: \(\left|-2\right|^{300}=2^{300}\)
\(\left|-4\right|^{150}=4^{150}=2^{300}\)
Do đó: \(\left|-2\right|^{300}=\left|-4\right|^{150}\)
b: \(\left|-2\right|^{300}=\left|-2\right|^{300}\)
So sánh A va B ma khong tính gia tri biet A= 2016*2016 va B =2015*2017
A = 2016 x 2016
A = (2015 + 1) x 2016
A = 2015 x 2016 + 2016
B = 2015 x 2017
B = 2015 x (2016 + 1)
B = 2015 x 2016 + 2015
Vì 2016 > 2015
=> A > B
A = \(2016^2\)
B = \(\left(2016-1\right)\left(2016+1\right)=2016\left(2016+1\right)-\left(2016+1\right)\)= \(2016^2+2016-2016-1\)= \(2016^2-1\)
\(\Rightarrow A>B\). Vậy A > B
Khong qui dong mau hay so sang
A=2015^2013+1/2015^2014+1 va B=2015^2014+1/2015^2015+1
A=2012/2013+2013/2014, B=2012+2013/2013+2014. So sanh A va B
Ta có: 1- 2012/2013=1/2013
1- 2013/2014=1/2014
Mà 1/2013>1/2014
vậy 2012/2013<2013/2014
cho a > 0 ,b>0 va a + b2012 = a2013 + b2013 = a2014 + b2014 . tinh a2015 + b2015
Ta có : \(a^{2012}+b^{2012}+a^{2014}+b^{2014}=\left(a^{2012}+a^{2014}\right)+\left(b^{2012}+b^{2014}\right)\ge2a^{2013}+2b^{2013}\)
( AD BĐT Cô - si cho a ; b dương )
Dấu " = " xảy ra \(\Leftrightarrow a^{2012}=a^{2014};b^{2012}=b^{2014}\) \(\Leftrightarrow a=b=1\left(a,b>0\right)\)
\(\Rightarrow a^{2015}+b^{2015}=1+1=2\)