6 So sánh m và n biết
m = \(\frac{2003}{2004}\) + \(\frac{2004}{2005}\) ; n = \(\frac{2003+2004}{2004+2005}\)
Ta có:
n = \(\frac{2003+2004}{2004+2005}\)
\(=>\) n = \(\frac{2003}{2004+2005}+\frac{2004}{2004+2005}\)
Vì \(\frac{2003}{2004}>\frac{2003}{2004+2005}\)
\(\frac{2004}{2005}>\frac{2004}{2004+2005}\)
\(=>\frac{2003}{2004}+\frac{2004}{2005}>\frac{2003}{2004+2005}+\frac{2004}{2004+2005}\)
\(=>\)m > n
Chúc bạn học tốt :)
Chứng minh nghiệm của phương trình sau là một số nguyên:
\(\frac{x-2}{2005}\) + \(\frac{x-3}{2004}\) + \(\frac{x-4}{2003}\) = \(\frac{x-2005}{2}\) + \(\frac{x-2004}{3}\) + \(\frac{x-2003}{4}\)
Giúp mình nha mình đang vội lắm!!!
Tìm x: a, \(\frac{x-2004}{2003}+\frac{x-2003}{2004}+\frac{x-2005}{2004}=3+\frac{2005}{2003}\)\(+\frac{2004}{2005}\)
c) 22/5 + 51/9 + 11/4 + 3/5 + 1/3 + 1/4
= 22/5 +3/5 +51/9 + 1/3 +11/4+1/4
= (22/5 +3/5) +(51/9 + 3/9) +(11/4+1/4)
= 25/5 +54/9 +12/4
= 5 +6 +3
= 14
d) (1/6 + 1/10 + 1/15) : (1/6 + 1/10 - 1/15)
= (5/30 + 3/30 +2/30 ) :(5/30 +3/30 -2/30)
= 10/30 : 6/30
= 1/3 : 1/5
= 5/3
Giải phương trình sau :
\(\frac{x^2-2008}{2007}+\:\frac{x^2-2007}{2006}+\frac{x^2-2006}{2005}=\:\frac{x^2-\:2005}{2004}+\:\frac{x^2-2004}{2003}+\:\frac{x^2-2003}{2002}\)
Ta có : \(\frac{x^2-2008}{2007}+\frac{x^2-2007}{2006}+\frac{x^2-2006}{2005}=\frac{x^2-2005}{2004}+\frac{x^2-2004}{2003}+\frac{x^2-2003}{2002}\)
=> \(\frac{x^2-2008}{2007}+1+\frac{x^2-2007}{2006}+1+\frac{x^2-2006}{2005}+1=\frac{x^2-2005}{2004}+1+\frac{x^2-2004}{2003}+1+\frac{x^2-2003}{2002}+1\)
=> \(\frac{x^2-2008}{2007}+\frac{2007}{2007}+\frac{x^2-2007}{2006}+\frac{2006}{2006}+\frac{x^2-2006}{2005}+\frac{2005}{2005}=\frac{x^2-2005}{2004}+\frac{2004}{2004}+\frac{x^2-2004}{2003}+\frac{2003}{2003}+\frac{x^2-2003}{2002}+\frac{2002}{2002}\)
=> \(\frac{x^2-1}{2007}+\frac{x^2-1}{2006}+\frac{x^2-1}{2005}=\frac{x^2-1}{2004}+\frac{x^2-1}{2003}+\frac{x^2-1}{2002}\)
=> \(\frac{x^2-1}{2007}+\frac{x^2-1}{2006}+\frac{x^2-1}{2005}-\frac{x^2-1}{2004}-\frac{x^2-1}{2003}-\frac{x^2-1}{2002}=0\)
=> \(\left(x^2-1\right)\left(\frac{1}{2007}+\frac{1}{2006}+\frac{1}{2005}-\frac{1}{2004}-\frac{1}{2003}-\frac{1}{2002}\right)=0\)
=> \(x^2-1=0\)
=> \(x^2=1\)
=> \(x=\pm1\)
Vậy phương trình có 2 nghiệm là x = 1, x = -1 .
Bài 1:Tìm x
2+\(\frac{2}{6}\)+\(\frac{2}{12}+\frac{2}{20}+........+\frac{2}{x\left(x+1\right)}=1\frac{2005}{2007}\)
Bài 2 :So sánh
a,\(\frac{2003}{2004}+\frac{2004}{2005}+\frac{2005}{2003}\)với 3
b,\(\frac{2005.2006}{2005.2006+1}\)và \(\frac{2006.2007}{2006.2007+1}\)
so sánh A và B
A = \(\frac{2003}{2004}+\frac{2004}{2005}\)và B = \(\frac{2003+2004}{2004+2005}\)
\(B=\frac{2003+2004}{2004+2005}=\frac{2003}{2004+2005}+\frac{2004}{2004+2005}\)
Ta có: \(\frac{2003}{2004}>\frac{2003}{2004+2005}\)
\(\frac{2004}{2005}>\frac{2004}{2004+2005}\)
\(\frac{2003}{2004}+\frac{2004}{2005}>\frac{2003+2004}{2004+2005}\)
\(A>B\)
Vậy A>B
\(\text{ Bài giải}\)
\(A=\frac{2003}{2004}+\frac{2004}{2005}=0,999500998 + 0,999501247=1.99900225\)
\(B=\frac{2003+2004}{2004+2005}=\frac{4007}{4009}=0,999501122\)
\(\text{Vì : }1,99900224>0,999501122\text{ nên }A>B\)
\(\text{Vậy : }A>B\)
Cho \(x,m,n\in N\)*. Hãy so sánh 2 tổng sau :
\(A=\dfrac{2004}{x^m}+\dfrac{2004}{x^n}\) và \(B=\dfrac{2005}{x^m}+\dfrac{2003}{x^n}\)
Chúc các bn học tốt!
\(B=\dfrac{2005}{x^m}+\dfrac{2003}{x^n}=\dfrac{2004}{x^m}+\dfrac{1}{x^m}+\dfrac{2004}{x^n}-\dfrac{1}{x^n}=A+\left(\dfrac{1}{x^m}-\dfrac{1}{x^n}\right)\)
\(\Rightarrow A< B\)
mình ko bt đúng hay sai nữa
\(A-B=\dfrac{1}{x^n}-\dfrac{1}{x^m}=\dfrac{x^m-x^n}{x^{m+n}}\)
+ Nếu m=n => A=B
+m>n => A>B
+m<n => A<B
so sánh A và B
A=\(\frac{20032}{2004}+\frac{2004}{2005}\)và B = \(\frac{2003+2004}{2004+2005}\)
\(A=\frac{20032}{2004}+\frac{2004}{2005}=9,99600798+0,999501247=10,9955092\)
\(B=\frac{2003+2004}{2004+2005}=\frac{4007}{4009}\)
\(\text{Vì : }10,9955092>1\text{ mà }\frac{4007}{4009}< 1\text{ nên }10,9955092>\frac{4007}{4009}\)
\(\text{Vậy : }A>B\)
giải giùm mình với:
So sánh A và B, biết
\(A=\frac{2003+2004}{2004+2005}\)
\(B=\frac{2003}{2004+2005}\)+\(\frac{2004}{2004+2005}\)
