Hi All,

I am doing a Precalculus course and this exercise is from schaum's outlines Precalculus textbook.

Please can someone help me understand how this guy came to his conclusion?

Attachment 24124The answerAttachment 24125

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- Jun 21st 2012, 02:00 AMSVDMRadicals and rationalizie
Hi All,

I am doing a Precalculus course and this exercise is from schaum's outlines Precalculus textbook.

Please can someone help me understand how this guy came to his conclusion?

Attachment 24124The answerAttachment 24125 - Jun 21st 2012, 02:19 AMGokuRe: Radicals and rationalizie

Now continue from there....(Evilgrin) - Jun 21st 2012, 02:41 AMbiffboyRe: Radicals and rationalizie
- Jun 21st 2012, 02:56 AMSVDMRe: Radicals and rationalizie
Hallo ou maat!

My head is spinning!

Thanks very much as I analyze this for the next 3 hours....

I never seen this done before! Not in the textbook anyway.

Stan - Jun 21st 2012, 03:51 AMGokuRe: Radicals and rationalizie
Remember that ...

- Jun 21st 2012, 12:03 PMSVDMRe: Radicals and rationalizie
Hi Guys thanks for the help!

I have another one that I can not solve. I don't find much help in text book and it does not help trying my own dodgy thinks so I hope to learn something from you all.

This time the stuffed me up with this...

Attachment 24131

? I tried to solve this but the answer is so wrong... - Jun 21st 2012, 12:16 PMPlatoRe: Radicals and rationalizie
- Jun 21st 2012, 12:19 PMSVDMRe: Radicals and rationalizie
Here ia another problem that keep me from sleeping.

Attachment 24132

what I do next brings me to the answer but i think it is dodgy and Ii would like to see how it is really doubt so Ii can be sure it is right.

Thanks again. - Jun 21st 2012, 02:04 PMReckonerRe: Radicals and rationalizie
- Jun 22nd 2012, 03:31 PMSVDMRe: Radicals and rationalizie
Hi again,

I am looking through the text book to find how you came to the conclusion to use a square of a difference in this case. the radical is cubed so I would thought to use differences of two cubes?

Or am I confused with the radicals somehow? If I disregard manipulating the numerator and just assume the difference of two cubes will remove the radicals my answer is correct. But I am missing something seriously with my understanding of polynomial manipulation because when I actually do the calculation. I get the result below which shows that something is not correct. (Crying)

Attachment 24136 - Jun 22nd 2012, 06:53 PMskeeterRe: Radicals and rationalizie
to rationalize the numerator of the fraction ...

note that the denominator can be factored as the difference of two cubes ...

can you finish? - Jun 22nd 2012, 08:39 PMSVDMRe: Radicals and rationalizie
- Jun 23rd 2012, 02:26 PMSVDMRe: Radicals and rationalizie
Please can you explain exactly why you came to this conlusion?

I am trying to understand what to look for to solve the problem myself but getting the answer still does not explain the process it takes to reach the conclusion.

Thanks again. - Jun 23rd 2012, 02:39 PMPlatoRe: Radicals and rationalizie