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pcondrat
 
 

Duplicate Deuces Challenge Problem

by pcondrat Sat Aug 11, 2007 4:57 pm

I am a little confused in the answer how you can simplifying the infinite part of the equation into x. How is it that the first equation can be simplified into to x= sqrt (2+x)? Could someone please help explain this a little more? Thanks! I appreciate the help.
StaceyKoprince
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by StaceyKoprince Sun Aug 12, 2007 3:25 pm

Hi, can you please post the entire text of the question and the answer choices? Thanks!
Stacey Koprince
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by Guest Tue Aug 14, 2007 10:24 am

skoprince Wrote:Hi, can you please post the entire text of the question and the answer choices? Thanks!


http://www.manhattangmat.com/ChallengeP ... hallID=307

The text of the question wouldn't post, but here is the link to it above. Thanks Stacey!
Harish Dorai
 
 

by Harish Dorai Sat Aug 18, 2007 1:10 am

Image

I am attaching the question image for the benefit of others. This is a tricky problem with infinite series.

To explain it , consider a simple equation without roots as shown below.

X = 1 + 1 + 1 + ......... (up to infinity)

Now you can call this X = 1 + X, because if you discard the first 1, you are still having 1 + 1 + ..... till infinity, which is again X as per the definition.

Infinity is basically something that is not countable. So you can say 1 subtracted from infinity = infinity, Or 1 added to Infinity is again Infinity.

I hope now the problem makes sense for you and how the equation became

X = Sqrt(2 + X). The reason is same as the above as in the 1 series.
StaceyKoprince
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Posts: 9360
Joined: Wed Oct 19, 2005 9:05 am
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by StaceyKoprince Mon Aug 20, 2007 6:23 pm

Thanks for posting the image, Harish, and for your explanation. pcondrat - let us know if Harish's explanation makes sense.
Stacey Koprince
Instructor
Director, Content & Curriculum
ManhattanPrep