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If f(x)=x+1/x ,\ \ x >0 , then its great...

If `f(x)=x+1/x ,\ \ x >0` , then its greatest value is `-2` (b) 0 (c) 3 (d) none of these

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We have
`f(x)=x+1 / x \Rightarrow f^{\prime}(x)=1-1 / x^{2} `
Substituting` f(x)=0`, we get `x=-1,1`.
Since `x>0`, no maximum value can be found
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