Find the first three terms in these expansions in ascending powers of x

a) (x+1/x)^6

b) In the expansion of (1+x/2)^n in ascending powers of x the coefficent of x^2 is 30. Find n.

Thanks in advance if you can help

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- Jan 30th 2006, 04:25 AMConfuzzled?Binomial expression help!
Find the first three terms in these expansions in ascending powers of x

a) (x+1/x)^6

b) In the expansion of (1+x/2)^n in ascending powers of x the coefficent of x^2 is 30. Find n.

Thanks in advance if you can help - Jan 30th 2006, 05:55 AMCaptainBlackQuote:

Originally Posted by**Confuzzled?**

RonL - Jan 30th 2006, 06:08 AMCaptainBlackQuote:

Originally Posted by**Confuzzled?**

So the coeff of in the expansion is:

,

which has solutions or .

I presume there is an implicit assumption that so

the answer would be .

RonL - Jan 30th 2006, 07:04 AMConfuzzled?
Thank you so much!