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Square roots and fractions

  • Thread starter Ry122
  • Start date
565
2
How do you get 3/sqrt2 from 3sqrt2/2?
 

Answers and Replies

138
0
Ask yourself what's (sqrt x)^2?
 
Math Is Hard
Staff Emeritus
Science Advisor
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hint: sqrt2/sqrt2 = 1
 
565
2
sorry dont follow
 
Integral
Staff Emeritus
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Try going the other way.
Start with
[tex] \frac 3 {\sqrt 2} [/tex]

to get

[tex] \frac {3 \sqrt 2} 2 [/tex]
 
1,341
3
If you're going from 3sqrt2/2 to 3/sqrt2 you're basically de-rationalizing the denominator.
 
HallsofIvy
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Homework Helper
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By definition [itex](\sqrt{2})^2= \sqrt{2}\sqrt{2}= 2[/itex]. That means that
[tex]\frac{\sqrt{2}}{2}= \frac{\sqrt{2}}{\sqrt{2}\sqrt{2}}[/tex]
 
Air
202
0
Ry122 said:
How do you get 3/sqrt2 from 3sqrt2/2?
[itex]\frac{3}{\sqrt 2} . \frac{\sqrt 2}{\sqrt 2} = \frac{3 \sqrt 2}{2}[/itex].

This is rationalising the denominator as you cannot have a surd on the denominator. The question that you are asking is how you get the reverse, de-rationalising the denominator. Try opposite steps to the one I shown.
 

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