Let be positive real numbers such that . Find the minimum value of the expression
Solution
To find the minimum value of the expression
given that are positive real numbers and , we proceed as follows:
First, we rewrite the expression:
Consider the function of a single variable:
Our goal is to minimize the sum .
We calculate the derivative of :
Setting to find critical points:
Thus, is a critical point where is extremized.
Checking the nature of this critical point, we compute the second derivative:
Evaluating :
This indicates that is a point of local minimum for .
Considering the condition , a natural symmetry suggests . Substituting these values back into the expression for :
Therefore, the minimum value of is:
This minimum is achieved when .
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