"rationalize" the denominator rather than the numerator

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Discussion Overview

The discussion centers around simplifying expressions involving radicals, specifically focusing on the approach of rationalizing either the numerator or the denominator. Participants explore different methods for simplifying the expression \(\frac{\sqrt{x} + 1}{\sqrt{x} - 1}\) and the operation involving \(\sqrt{x}(\sqrt{x} + 1)(2\sqrt{x}-1)\).

Discussion Character

  • Mathematical reasoning, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant requests assistance in simplifying the expression \(\frac{\sqrt{x} + 1}{\sqrt{x} - 1}\) and performing operations with \(\sqrt{x}(\sqrt{x} + 1)(2\sqrt{x}-1)\).
  • Another participant provides a simplification of the first expression, resulting in \(\frac{x-1}{x - 2\sqrt{x} + 1}\) and simplifies the second expression to \(2x\sqrt{x} + x - \sqrt{x}\).
  • A different participant suggests rationalizing the denominator instead of the numerator, leading to the expression \(\frac{x + 2\sqrt{x} + 1}{x - 1}\).
  • One participant questions when it is appropriate to rationalize the denominator versus the numerator.
  • Another participant asserts that simplified form typically means rationalizing the denominator and provides a further simplification of the expression to \(\frac{(1+\sqrt{x})^2}{x-1}\).

Areas of Agreement / Disagreement

Participants express differing views on the preferred method of rationalization, with some advocating for rationalizing the denominator while others suggest rationalizing the numerator. The discussion remains unresolved regarding the best approach to take in different scenarios.

Contextual Notes

Some assumptions about the conditions under which rationalization is preferred are not explicitly stated, and the discussion does not clarify the implications of choosing one method over the other.

powp
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Hello All

I get to thrown off when there is a question with radicals . Can you please help

Simplify the following

[tex]\frac{\sqrt{x} + 1}{\sqrt{x} - 1}[/tex]


and Preform the indicated operations and simplfy


[tex]\sqrt{x}(\sqrt{x} + 1)(2\sqrt{x}-1)[/tex]

Thanks

P
 
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the first:

[tex]\frac{\sqrt{x} + 1}{\sqrt{x} - 1}[/tex]

[tex]\frac{(\sqrt{x} + 1)(\sqrt{x} - 1)}{(\sqrt{x} - 1)(\sqrt{x} - 1)}[/tex]

[tex]\frac{x-1}{x -2 \sqrt{x} +1}[/tex]

the second:

[tex]\sqrt{x}(\sqrt{x} + 1)(2\sqrt{x}-1)[/tex]

[tex]\sqrt{x}(2x+ \sqrt{x}-1)[/tex]

[tex]2x \sqrt{x}+x- \sqrt{x}[/tex]
 
I would have been inclined to "rationalize" the denominator rather than the numerator:
[tex]\frac{\sqrt{x}+1}{\sqrt{x}-1}= \frac{(\sqrt{x}+1)(\sqrt{x}+1)}{(\sqrt{x}-1})(\sqrt{x}+1)}= \frac{x+ 2\sqrt{x}+1}{x-1}[/tex]
 
thanks that's the answers I got but was not sure

When would you "rationalize" the denominator over the numerator or the other way around.
 
Generally simplified form means always "rationalizing" the denominator. Also you can simplify a little bit more. [tex]\frac{x+ 2\sqrt{x}+1}{x-1} = \frac{ (1+\sqrt{x})^2}{x-1}[/tex]
 

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