Calculating Real Values of Expressions

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Discussion Overview

The discussion revolves around understanding how to calculate the least possible real value of mathematical expressions, particularly focusing on a specific quadratic expression involving real numbers and square roots. The scope includes theoretical exploration and mathematical reasoning.

Discussion Character

  • Exploratory, Technical explanation, Mathematical reasoning

Main Points Raised

  • One participant expresses uncertainty about the definition of a real value of an expression and seeks guidance on finding the least possible real value.
  • Another participant suggests taking the derivative of the expression, setting it to zero, and checking occurrences as a method for finding minimum values, while noting that there are varying levels of complexity in the answers.
  • A specific expression is presented by a participant, which is a quadratic expression with square root terms, asking for the least possible real value.
  • Another participant points out that the last two terms of the expression cancel each other out, indicating a potential misunderstanding in the original formulation.
  • One participant comments that the cancellation simplifies the problem of finding the minimum value.
  • A later reply proposes a specific value of n and a corresponding value for the expression, questioning if this is accurate.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct formulation of the expression or the method for finding the least possible real value, as there are differing interpretations and approaches presented.

Contextual Notes

There is a lack of clarity regarding the original expression due to the cancellation of terms, which may affect the discussion on finding the minimum value. Additionally, the complexity of the expression and the applicability of calculus techniques are not fully resolved.

omega360
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i'm not sure whether this is the right place to post this but i need to know what a real value of an expression is. also can anyone tell how i could find the least possible real value of an expression.
 
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omega360 said:
also can anyone tell how i could find the least possible real value of an expression.

Without context, how could we know how to answer this?

My best guess would be "take the derivative, set it equal to zero, and check each occurrence". There are less advanced answers (for those who don't know calculus yet) and more advanced answers (Richardson's theorem says if the expression is sufficiently (not very!) complicated, it's undecidable in general).
 
could you tell me how to find the least possible real value of this expression:(where n is a real number)
(n squared) minus (3n) plus [the square root of (n – 3)] minus [the square root of (n – 3)]
 
[tex]n^2 - 3n + \sqrt{n-3} - \sqrt{n-3}[/tex]is what you wrote, and the last two terms cancel so it probably wasn't what you wanted.
 
Well, that would make it easy to find the minimum...
 
Agreed. Just to make sure we're on the same page, the answer would be

n=3/2, val=-9/4

True story?
 

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