What Is the Minimal Value of the Summation Involving Absolute Values?

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The discussion centers on finding the minimal value of the summation involving absolute values, specifically the expression ∑|x-k| for k ranging from 0 to 2009. A participant suggests that the optimal value of x is approximately 18, derived from considering x as the midpoint between 0 and the square root of 2009. However, there is confusion regarding the relationship between the variables x, k, and n, as well as the interpretation of the original problem. Clarification is sought on whether the formulation of the problem is accurate and whether additional context is needed to solve it effectively. The conversation highlights the complexities involved in minimizing the summation and the need for clearer definitions.
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Homework Statement


Find the minimal value of :
^{2009}_{n=0}\sum \left| x-k \right|
Such that x is a real value.




Homework Equations





The Attempt at a Solution



x must be the mid pt of sqroot of 2009 and 0
which is approx 18
 
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Any additional information, related equations? Is that the original problem?

Do you mean:

\sum_{k=0}^{2009}|x-k|=|x-0|+|x-1|+|x-2|+...+|x-2009| ??

And why do you think that x must be mind point of \sqrt{2009} and 0?
 


Дьявол said:
Any additional information, related equations? Is that the original problem?

Do you mean:

\sum_{k=0}^{2009}|x-k|=|x-0|+|x-1|+|x-2|+...+|x-2009| ??

And why do you think that x must be mind point of \sqrt{2009} and 0?
Nope,the given information is written in my previous post.
For it says the minimal value, and by taking modulus , it is the distance from x to the root of the varying square root. therefore midpt ought to yield the minimal distance overall.
Correct me if i am wrong (=
 


Your original question includes the variables x and k in the absolute value and n as an index of the summation. Is this intentional? Is there any relation between k, n, and x? Over which variable(s) are we minimizing? As stated, there is not sufficient information to help answer your question.

--Elucidus
 
Since ##px^9+q## is the factor, then ##x^9=\frac{-q}{p}## will be one of the roots. Let ##f(x)=27x^{18}+bx^9+70##, then: $$27\left(\frac{-q}{p}\right)^2+b\left(\frac{-q}{p}\right)+70=0$$ $$b=27 \frac{q}{p}+70 \frac{p}{q}$$ $$b=\frac{27q^2+70p^2}{pq}$$ From this expression, it looks like there is no greatest value of ##b## because increasing the value of ##p## and ##q## will also increase the value of ##b##. How to find the greatest value of ##b##? Thanks

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