Minimum value of f ( x ) = x + x 1 for x > 0 and x = 1 .
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Its not "not defined" but "does not exist"
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I agree with you ..
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great. Wait can normal users change their questions choices?
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@Aareyan Manzoor – No , I asked staff member to change then he changed.
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@Yash Dev Lamba – yeah thats fine.
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@Aareyan Manzoor – by the way thnx for suggestion ..
@Yash Dev Lamba – You said x = 1 but if we take x = 0 . 9 9 9 9 9 9 7 then it's minimum value is near 2
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@Department 8 – Taking value more closer to 1 gives value near 2 but it cannot be 2 it can 1 . 9 9 9 9 9 9 9 9 9 9 9 9 7 , 2 . 0 0 0 0 0 0 0 0 0 1 (there are such infinte value near 2 ) . In that case we says that minimum does not exists.
Using calculus,
Let, y = x + x − 1
d x d y = 1 − x − 2
For minima the derivative must equal to zero,
1 − x − 2 = 0
x = 1 , − 1
But in the question we are given x = 1 and x > 0
Hence the minima doesn't exists.
I thought your d x d y is wrong , correct d x d y = 1 − x 2 1
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Thanks! I was actually thinking about something else while writing the solution.
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Now there is a flaw in solution too
In 6 t h line you write x = 1 , indeed x = 1 , − 1
then you have to reject x = − 1 becuase x > 0
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@Yash Dev Lamba – This proves my previous point😛. Thanks again.
Using the fact that 0.9999... is actually equal to 1, we can say that 0.000...0001 is equal to 0. As minimum value of X is 0.000...0001 and the value is 0, the answer is Does not Exist.
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Using A M ≥ G M
2 x + x 1 ≥ x . x 1
⟹ 2 x + x 1 ≥ 1
⟹ x + x 1 ≥ 2
equality holds when x = x 1 ⟹ x = ± 1
But x > 0 and also x = 1
⟹ m i n ( x + x 1 ) = 2
So the range of given funtion is ( 2 , ∞ ) not [ 2 , ∞ ) .
Then for obvious reasons its minimum value is does not exist .