Can someone please explain to me how this works?

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Discussion Overview

The discussion revolves around the mathematical expression √(x² - y²) and the process of factoring out x from this expression. Participants explore the reasoning behind the correct method of factoring and the implications of manipulating the terms within the square root.

Discussion Character

  • Mathematical reasoning
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests that factoring out x from √(x² - y²) should be straightforward, as the square root of a square is the base, leading to the incorrect expression x√(1 - y²).
  • Another participant explains that when dealing with (x - y)², x cannot be factored out because it also affects y, illustrating the complexity of the expression.
  • A different participant introduces the concept of the multiplicative inverse, stating that to factor out x², one must divide by x² and multiply by its reciprocal, leading to the expression x²(1 - y²/x²).
  • There is a repeated inquiry about how dividing y² by x² resolves the expression, indicating a lack of clarity on this point among participants.
  • A later reply expresses understanding after the explanation of the multiplicative inverse and the equivalent expression, suggesting some clarity was achieved.

Areas of Agreement / Disagreement

The discussion contains multiple viewpoints regarding the correct method of factoring and the implications of manipulating the expression. There is no consensus on the reasoning behind dividing y² by x², as some participants seek further clarification.

Contextual Notes

Participants express uncertainty about the mathematical steps involved in factoring and the implications of the multiplicative inverse, indicating that some assumptions may not be fully articulated.

zeromodz
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If let's say we have the following expression

√(x^2 - y^2)

If I wanted to factor out x, then why can't I just take x out because a square root of a square is the base.

x√(1 - y^2)

But it turns out that the answer to this is incorrect and the answer to factoring out x is.

x√(1 - y^2/x^2)

Why is it I divide by y^2, by x^2 ? I have no idea! Thanks.
 
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Suppose it was (x-y)^2 you couldn't take out the x because it also effects the y,
ie. (x-y)^2 = (x-y)(x-y) = x^2 -2xy + y^2

and sqrt(x^2-y^2) is (x^2-y^2)^0.5 , same principle the x goes with the y
 
Use basic principles about fractions and the meaning of Multiplicative Inverse. You want to find an equivalent expression to your original one but you wish to show a factor of x2.

Look at the expression under the radical symbol.
[tex]x^2 - y^2[/tex]

If you DIVIDE by x2 then you must also multiply by the reciprocal of x2 to state the same meaning of the expression.
[tex]x^2 (1 - \frac{y^2}{x^2})[/tex]

With that you can then find the square root can be simplified with a factor of just x outside of the radical.
 
NobodySpecial said:
Suppose it was (x-y)^2 you couldn't take out the x because it also effects the y,
ie. (x-y)^2 = (x-y)(x-y) = x^2 -2xy + y^2

and sqrt(x^2-y^2) is (x^2-y^2)^0.5 , same principle the x goes with the y

I understand, but how does dividing y^2 by x^2 resolve the expression?
 
symbolipoint said:
Use basic principles about fractions and the meaning of Multiplicative Inverse. You want to find an equivalent expression to your original one but you wish to show a factor of x2.

Look at the expression under the radical symbol.
[tex]x^2 - y^2[/tex]

If you DIVIDE by x2 then you must also multiply by the reciprocal of x2 to state the same meaning of the expression.
[tex]x^2 (1 - \frac{y^2}{x^2})[/tex]

With that you can then find the square root can be simplified with a factor of just x outside of the radical.

Okay thank you so much, I understand now!
 

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