How can I rationalize the numerator in this fraction with square roots?

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JettyZ
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Alright, so I've go this question where I'm to rationalize the numerator. [Grade 10 Level]

Homework Statement


(1+sqrt(2)-sqrt(3))/(sqrt(2))
http://www.myalgebra.com/math_image.aspx?p=SMB02FSMB031+SMB02RSMB032SMB02rSMB03-SMB02RSMB033SMB02rSMB03SMB10SMB02RSMB032SMB02rSMB03SMB02fSMB03?p=74?p=42

Homework Equations


The Attempt at a Solution


I'm not going to type all of my entire failed attempts. Though, I did try seperating this into two fractions, but I don't think that'd be useful. I also multiplied the numerator and denominator by the numerator's conjugate, I think. Although I'm not sure:
(1+sqrt(2)-sqrt(3))/(sqrt(2))*((sqrt(2))+(sqrt(3)))/((sqrt(2))+(sqrt(3)))
http://www.myalgebra.com/math_image.aspx?p=SMB02FSMB031+SMB02RSMB032SMB02rSMB03-SMB02RSMB033SMB02rSMB03SMB10SMB02RSMB032SMB02rSMB03SMB02fSMB03*SMB02FSMB03(SMB02RSMB032SMB02rSMB03)+(SMB02RSMB033SMB02rSMB03)SMB10(SMB02RSMB032SMB02rSMB03)+(SMB02RSMB033SMB02rSMB03)SMB02fSMB03?p=164?p=42
I think the positive one in the equation is what's causing me to lose.
 
Last edited by a moderator:
on Phys.org
JettyZ said:
Alright, so I've go this question where I'm to rationalize the numerator. [Grade 10 Level]

Homework Statement


(1+sqrt(2)-sqrt(3))/(sqrt(2))
http://www.myalgebra.com/math_image.aspx?p=SMB02FSMB031+SMB02RSMB032SMB02rSMB03-SMB02RSMB033SMB02rSMB03SMB10SMB02RSMB032SMB02rSMB03SMB02fSMB03?p=74?p=42


Homework Equations





The Attempt at a Solution


I'm not going to type all of my entire failed attempts. Though, I did try seperating this into two fractions, but I don't think that'd be useful. I also multiplied the numerator and denominator by the numerator's conjugate, I think. Although I'm not sure:
(1+sqrt(2)-sqrt(3))/(sqrt(2))*((sqrt(2))+(sqrt(3)))/((sqrt(2))+(sqrt(3)))
http://www.myalgebra.com/math_image.aspx?p=SMB02FSMB031+SMB02RSMB032SMB02rSMB03-SMB02RSMB033SMB02rSMB03SMB10SMB02RSMB032SMB02rSMB03SMB02fSMB03*SMB02FSMB03(SMB02RSMB032SMB02rSMB03)+(SMB02RSMB033SMB02rSMB03)SMB10(SMB02RSMB032SMB02rSMB03)+(SMB02RSMB033SMB02rSMB03)SMB02fSMB03?p=164?p=42



I think the positive one in the equation is what's causing me to lose.

Are you sure they don't want you to rationalize the denominator instead? Why would you want to rationalize the numerator of a fraction?
 
Last edited by a moderator:
The teacher just told us to... It's homework.
 
JettyZ said:
The teacher just told us to... It's homework.

Very weird, but fair enough. I think you had the right idea to separate it into multiple fractions. I'd split it up into all 3 fractions, rationalize the numerator of each, and look for any re-combinations (if there are any) that do not re-introduce radicals in the numerator(s). Not sure that's what they want, but it's all that I see at the moment.
 
Oh, so I separated it into three fractions and I think I just won.

http://www.myalgebra.com/math_image.aspx?p=2+SMB02FSMB031-SMB02RSMB033SMB02rSMB03SMB10SMB02RSMB032SMB02rSMB03SMB02fSMB03?p=66?p=42

Thanks :)
 
Last edited by a moderator:
JettyZ said:
Oh, so I separated it into three fractions and I think I just won.

http://www.myalgebra.com/math_image.aspx?p=2+SMB02FSMB031-SMB02RSMB033SMB02rSMB03SMB10SMB02RSMB032SMB02rSMB03SMB02fSMB03?p=66?p=42

Thanks :)

But your answer still has a radical in a numerator... (and I'm not sure your answer is equal to the original problem either... have you tried putting both forumulas into your calculator to check that they are equal?)
 
Last edited by a moderator:
berkeman said:
But your answer still has a radical in a numerator... (and I'm not sure your answer is equal to the original problem either... have you tried putting both forumulas into your calculator to check that they are equal?)

Oh... You're right. I guess that's a problem then.
 
Hint:

Start with noting:
[tex]\frac{1+\sqrt{2}-\sqrt{3}}{\sqrt{2}}=\frac{(1+(\sqrt{2}-\sqrt{3}))(1-(\sqrt{2}-\sqrt{3}))}{\sqrt{2}(1-(\sqrt{2}-\sqrt{3}))}[/tex]

The numerator you'll end up with will be easy to rationalize
 
arildno said:
Hint:

Start with noting:
[tex]\frac{1+\sqrt{2}-\sqrt{3}}{\sqrt{2}}=\frac{(1+(\sqrt{2}-\sqrt{3}))(1-(\sqrt{2}-\sqrt{3}))}{\sqrt{2}(1-(\sqrt{2}-\sqrt{3}))}[/tex]

The numerator you'll end up with will be easy to rationalize

Thanks, I noticed that your method would require more steps to complete than:
[tex]\frac{1+\sqrt{2}-\sqrt{3}}{\sqrt{2}}=\frac{((1+\sqrt{2})-\sqrt{3})((1+\sqrt{2})+\sqrt{3})}{\sqrt{2}((1-\sqrt{2})-\sqrt{3})}[/tex]

Anyways so I've solved it, thanks for the help. :)
 
As a final note, we may simplify this very much:
[tex]\frac{1+\sqrt{2}-\sqrt{3}}{\sqrt{2}}=\frac{(1+(\sqrt{2}-\sqrt{3}))(1-(\sqrt{2}-\sqrt{3}))}{\sqrt{2}(1-(\sqrt{2}-\sqrt{3}))}=\frac{2(\sqrt{6}-2)}{\sqrt{2}(1-(\sqrt{2}-\sqrt{3}))}=\frac{4}{\sqrt{2}(1-(\sqrt{2}-\sqrt{3}))(\sqrt{6}+2)}[/tex]

By multiplying out the denumerator, you'll end up with:
[tex]\frac{1+\sqrt{2}-\sqrt{3}}{\sqrt{2}}=\frac{2}{1+\sqrt{2}+\sqrt{3}}[/tex]
 
JettyZ said:
Thanks, I noticed that your method would require more steps to complete than:
[tex]\frac{1+\sqrt{2}-\sqrt{3}}{\sqrt{2}}=\frac{((1+\sqrt{2})-\sqrt{3})((1+\sqrt{2})+\sqrt{3})}{\sqrt{2}((1-\sqrt{2})-\sqrt{3})}[/tex]

Anyways so I've solved it, thanks for the help. :)
This won't work!

Unless the -signs in the denumerator really should be +signs, in which case it works nicely.