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What is x+1/x , If x^2+1/x^2=62 ??

 Sep 21, 2016
 #1
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Look under your first post!!.

 Sep 21, 2016
 #2
avatar+111437 
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What is x+1/x , If x^2+1/x^2=62 ??

 

(x + 1/x) (x + 1/x)  =

 

(x + 1/x)^2  =   expand this

 

x^2 + 2 +   1/x^2    rearrange as

 

x^2 + 1/x^ 2 + 2     substitute

 

62 + 2   =

 

64

 

Therefore 

 

(x + 1/x)^2  = 64      take the square root of both sides

 

x + 1/x   = ±√64  =  ± 8

 

 

cool cool cool

 Sep 21, 2016
 #3
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Cphill: Is it any easier or simpler to find x from x^2+1/x^2=62, which comes to: 4 + sqrt(15), then add its reciprocal to it which gives you=8. No?.

 Sep 21, 2016

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