(1/2x-1004)^2008 = (1/2x-1004)^2006
Tìm x biết: (1/2x-1004)^2008 = (1/2x-1004)^2006 a c giúp e với
\(\left(\frac{1}{2x}-1004\right)^{2008}=\left(\frac{1}{2x}-1004\right)^{2006}\)
\(\Rightarrow\left(\frac{1}{2x}-1004\right)^{2008}-\left(\frac{1}{2x}-1004\right)^{2006}=0\)
\(\Rightarrow\left(\frac{1}{2x}-1004\right)^{2006}.\left(\frac{1}{2x}-1004\right)^2-\left(\frac{1}{2x}-1004\right)^{2006}=0\)
\(\Rightarrow\left(\frac{1}{2x}-1004\right)^{2006}.\left[\left(\frac{1}{2x}-1004\right)^2-1\right]=0\)
\(\Rightarrow\left(\frac{1}{2x}-1004\right)^{2006}=0\) hoặc \(\left(\frac{1}{2x}-1004\right)^2-1=0\)
TH1: \(\left(\frac{1}{2x}-1004\right)^{2006}=0\)
\(\Rightarrow\frac{1}{2x}-1004=0\)
\(\Rightarrow\frac{1}{2x}=1004\)
\(\Rightarrow2x=1:1004=\frac{1}{1004}\)
\(\Rightarrow x=\frac{1}{2008}\)
TH2: \(\left(\frac{1}{2x}-1004\right)^2-1=0\)
\(\Rightarrow\left(\frac{1}{2x}-1004\right)^2=1\)
\(\Rightarrow\frac{1}{2x}-1004=1\) hoặc \(\frac{1}{2x}-1004=-1\)
\(\Rightarrow\frac{1}{2x}=1005\) hoặc \(\frac{1}{2x}=1003\)
\(\Rightarrow x=\frac{1}{2010}\) hoặc \(x=\frac{1}{2006}\)
Vậy \(x\in\left\{\frac{1}{2010};\frac{1}{2008};\frac{1}{2006}\right\}\)
(1/2x-1004)^2008 = (1/2x-1004)^2000
a) [-2008*57+1004(-86)]/[32*74+16*(-48)]
b)1+2-3-4+5+6-7-8+9+10-...+2006-2007-2008+2009
a) [ -2008 x 57 + 1004 x (-86) ] : [ 32 x 74 + 16 x (-48) ]
b) 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 +10 - ......................... + 2006 - 2007 - 2008 + 2009
Cho A =1/1-1/2+1/3-1/4+...+1/2005+1/2006
B=(1/1+1/2+1/2006)-2x(1/2+1/4+...+1/2006)
a)So sánh A và B
b)Chứng minh rằng A=1/1004+1/1005+...1/2006
a,\(A=1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2005}-\frac{1}{2006}\)
\(A=\left(1+\frac{1}{3}+...+\frac{1}{2005}\right)-\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{2006}\right)\)
\(A=\left(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2006}\right)-2\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{2006}\right)\)
\(=B\left(ĐPCM\right)\)
b, \(A=\left(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2006}\right)-\left(1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{1003}\right)\)
\(A=\frac{1}{1004}+\frac{1}{1005}+...+\frac{1}{2006}\)
ui ghi lộn, chữ đpcm chuyển xuống dòng cuối cùng nhé :v
Cho : A = 1/1*2+1/3*4+1/5*6+.....+1/2003*2004+1/2005*2006
B=1/1004*2006+1/1005*2005+1/1006*2004+....+1/2006*1004
Tinh: A/B
Tính nhanh: a) 1004 . 2009 +1005 / 1005 .2009- 1004
b) 1004 .2010 +1 / 1006.2009 - 3013
c) 2008 . 2008 -3 / 2007 .2009 - 2
Mng mọi người giúp mình bài toán này!!! Mình đang cần gấp.
a, 1004 .2009 + 1005 = (1005-1) .2009 +1005
= 1005 .2009 -2009 +1005
= 1005 .2009 -1004
Vậy ( 1004 .2009 +1005) / (1005 .2009 -1004) =1
b, 1004 .2010 +1 = 1004 .2009 +1004 +1
= (1006 -2) .2009 +1005
= 1006 .2009 -2 .2009 +1005
= 1006 .2009 -4008 +1005
= 1006 .2009 -3013
Vậy (1004 .2010 +1) / (1006 .2009 -3013) = 1
c, 2007 .2009 -2 = 2007.(2008+1) -2
= 2007.2008 +2007 -2
= 2007.2008 +2005
= (2008-1) .2008 +2005
= 2008 .2008 -2008 +2005
= 2008 .2008 -3
Vậy (2008 .2008 -3) / (2007 .2009 -2) =1
dựa và mà làm nha bạn
1005.2009-1004=1004.2009+2009-1004=1004.2009+1005
=> a=1
A=2008.(1/2007-1000/1004)-2009.(1/2007-2)
\(A=2008.\left(\frac{1}{2007}-\frac{1000}{1004}\right)-2009.\left(\frac{1}{2007}-2\right)\)
\(\Rightarrow A=2008.\frac{1}{2007}-2000-2009.\frac{1}{2007}+4018\)
\(\Rightarrow A=\frac{1}{2007}.\left(2008-2009\right)-2000+4018\)
\(\Rightarrow A=\frac{1}{2007}.\left(-1\right)-2000+4018\)
\(\Rightarrow A\approx2018\)
2008.(\(\dfrac{1}{2007}\)-\(\dfrac{2009}{1004}\))-2009.(\(\dfrac{1}{2007}\)-2)
\(=\dfrac{2008}{2007}-2\cdot2009-\dfrac{2009}{2007}+2009\cdot2\)
=-1/2007