Questions about the world of GMAT Math from other sources and general math related questions.
sarathsasikumar
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Number of terms

by sarathsasikumar Fri Jan 15, 2010 8:50 pm

General question :

How do you find the number of terms in(a1+a2+a3....an)^m ?
jssaggu.tico
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Re: Number of terms

by jssaggu.tico Mon Jan 18, 2010 12:59 pm

This question is out of scope as per GMAT is concerned.
But, if you still need answer, let me know.
I promise that it will take forever to digest it because of huge series of summation gets formed with lot of variables with explanation.

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sarathsasikumar
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Re: Number of terms

by sarathsasikumar Mon Jan 18, 2010 2:55 pm

Let me throw some specifics in - How to you find the number of terms in say (a+b+c)^50 ?
jssaggu.tico
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Re: Number of terms

by jssaggu.tico Tue Jan 19, 2010 11:33 am

Considering this (a+b+c)^50.

By binomial theorem, we know that (a+b)^n has n+1 terms.
Now in our case lets consider 'b+c' as B'.
Then we have, (a+B')^50 which has 50+1 terms and out of these 50 terms are dependent on B'. So those 50 terms further will be like (b+c), (b+c)^2, (b+c)^3.......................(b+c)^50.

So we have total number of terms as 1+(1+1)+(2+1)...............(50+1)=1326 Ans

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RonPurewal
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Re: Number of terms

by RonPurewal Sat Jan 30, 2010 8:26 am

this whole problem is WAY WAY WAY beyond the purview of the gmat. in fact, if you're studying this kind of stuff, then i would venture so far as to say that most of the math you're studying is a complete waste of your time, at least as regards the gmat. (i.e., if you're studying this, then you are almost certainly also studying many, many other points of advanced math that would never show up on the test.)

if you're studying books that contain this sort of thing, then you should close those books, and get out books that are designed for the gmat.

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since this problem has no possible connection to the gmat, we probably shouldn't post a solution here. (we don't want forum readers to study irrelevant topics.)