tìm x thuộc N biết 1/2013.x+1+1/2+1/6+....+1/2012.2013=2
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Tìm x biết : 1/2013.x +1+1/2+1/6+1/12+...+1/2012.2013=2
tìm x
1/2013 *x+1+1/2+1/6+1/12+...+1/2012.2013=2
1/2013.x+1+1/2+1/6+1/12+...+1/2012.2013=2
1/2013.x+1+1/1.2+1/2.3+1/3.4+...+1/2012.2013=2
1/2013.x+1+1-1/2+1/2-1/3+1/3-1/4+...+1/2012-1/2013=2
1/2013.x+2-1/2013=2
1/2013.x =2-2+1/2013
1/2013.x =1/2013
=>2013.x=2013
=> x=1
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\(\Rightarrow\frac{1}{2013.x}+1+1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+.....+\frac{1}{2012}-\frac{1}{2013}=2\)
\(\Rightarrow\frac{1}{2013.x}+2-\frac{1}{2013}=2\)
\(\Rightarrow\frac{1}{2013.x}=2-2+\frac{1}{2013}\)
\(\Rightarrow\frac{1}{2013.x}=\frac{1}{2013}\)
\(\Rightarrow2013.x=2013\)
\(\Rightarrow x=1\)
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Tìm x
\(\frac{1}{2013}x+1+\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{2012.2013}=2\)
\(\frac{1}{2013}x+1+\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{2012.2013}=2\)
\(\frac{1}{2013}x+1+(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{2012.2013})=2\)
\(\frac{1}{2013}x+1+\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2012}-\frac{1}{2013}\right)=2\)
\(\frac{1}{2013}x+1+\left(1-\frac{1}{2013}\right)=2\)
\(\frac{1}{2013}x+1+1-\frac{1}{2013}=2\)
\(\frac{1}{2013}x-\frac{1}{2013}+2=2\)
\(\frac{1}{2013}.\left(x-1\right)=2-2\)
\(\frac{1}{2013}.\left(x-1\right)=0\)
=> x - 1 = 0
x = 1
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\(\frac{1}{2013}x+1+\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+...+\frac{1}{2012.2013}=2\)
\(\frac{1}{2013}x+\left(1+\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{2012.2013}\right)=2\)
\(\frac{1}{2013}x+\left(1+1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2012}-\frac{1}{2013}\right)=2\)
\(\frac{1}{2013}x+\left(1-\frac{1}{2013}\right)=2\)
\(\frac{1}{2013}x+\frac{2012}{2013}=2\)
\(\frac{1}{2013}x=2-\frac{2012}{2013}\)
\(\frac{1}{2013}x=\frac{2014}{2013}\)
\(x=\frac{2014}{2013}:\frac{1}{2013}\)
=> x=2014
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1/2013.x+1+1/2+1/6+1/12+...+1/2012.2013=2
Xem thêm câu trả lời
1/5.8+1/8.11+....+1/y(y+3)=98/1545 tìm x,y
2x+7/6+13/12+21/20+31/30+43/42+57/56+73/72+91/90=10
1/2013.x+1+1/2+1/6+....+1/2012.2013=2
1+1/3+1/6+1/10+...+1/2012.2013=2
1/21+1/28+1/36+...+2/x(x+1)=2/9
ai nhanh mình tik cho
Tìm x thuộc Z biết 1/3+1/6+1/10+...+1/x(x+1)=2013/2015
2/6+2/12+2/20+...+2/x(x+2)=2013/2015
2(1/2.3+1/3.4+...+1/x(x+1))=2013/2015
2(1/2-1/3+1/3-1/4+...+1/x-1/x+1)=2013/2015
2(1/2-1/x+1)=2013/2015
1/2-1/x+1=2013/2015:2
1/2-1/x+1=2013/4030
1/x+1=1/2-2013/4030
1/x+1=1/2015
Suy ra x+1=2015
x=2014
Vậy x=2014
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Tìm x biết:
x + (x+1) + (x+2) + (x+3) +...+ (x+2012) = 2012.2013
Ta có : x + (x + 1) + (x + 2) + .... + (x + 2012) = 2012.2013
<=> (x + x + x + ..... + x) + (1 + 2 + .... + 2012) = 2012.2013
<=> 2013x + \(\frac{2012.2013}{2}\) = 2012.2013
<=> 2013x = 2012.2013 - \(\frac{2012.2013}{2}\)
<=> 2013x = 2025078
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Câu 1: Tìm x, y, z biết:
(3x-5)^2010+(y-1)^2012+(x-z)^2014=0
Câu 2: tìm x, y thuộc N biết:
116-y^2=7(x-2013)^2
Tìm x biết
1/3+1/6+1/10+...+2/x(x+1)=2013/2014
1/3 = 2/6 = 2/(2x3) = 2/2 - 2/3
1/6 = 2/12 = 2/(3x4) = 2/3 - 2/4
...
2/x(x + 1) = 2/x - 2/(x +1)
Do đó:
1/3 + 1/6 + ... + 2/x(x+1) = 2/2 - 2/3 + 2/3 - 2/4 + ... +2/x - 2/(x + 1) = 2/2 - 2/(x+1)
suy ra 1 - 2/(x + 1) = 2013/2014
x= 4027
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