Description of binomial expansion

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Homework Help Overview

The discussion revolves around finding the coefficient of \(x^n\) in the expansions of \((1+x)^{-1}\) and \((1-x)^{-1}\), which falls under the topic of binomial expansion.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss using the general term of the binomial expansion and express uncertainty about the correctness of their methods. There are questions about the appropriate term to use for the expansions and concerns about obtaining the correct signs in their answers.

Discussion Status

Some participants have offered guidance on using the binomial expansion formula, while others are exploring different interpretations and approaches to the problem. There is a mix of attempts to clarify the method and questions about specific terms in the expansion.

Contextual Notes

There is a suggestion that participants should make an attempt to solve the problem to facilitate assistance, indicating a learning-focused environment. Additionally, there is a reference to the infinite geometric sum, which may relate to the expansions being discussed.

squids
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what will be the coefficient of the x^n in the expansion of (1+x)^-1 and(1-x)^-1. Please answer it separately..
 
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According to the spirit of this forum, an attempt on your part will help to encourage someone to help you.
 
i used the general term as tr=C(n,r) a^(n-r)*x^r. however i could not have a final answer as i supposed this method is not approate so there may be other wayz to solve. and using above formula i always got the answer without the appropriate sign..could anyone help for it..
 
You can use

(1 + x)[itex]^{m}[/itex] = 1 + mx/(1!) + m(m - 1)x[itex]^{2}[/itex]/(2!) + ...
 
ya i used it but what should be the nth term...i have no idea...pls give me some..
 
squids said:
what will be the coefficient of the x^n in the expansion of (1+x)^-1 and(1-x)^-1. Please answer it separately..

I am sure you have seen the answers to these questions, even before you ever heard of the binomial expansion!

RGV
 
I believe Ray Vickson is referring to the formula for the infinite geometric sum.
 

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