# Binomial expansion question

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#1
"Find the value of the term in the expansion of (x-(1/x))^8 which is independent of x."

I've been using the nCr function and it worked great so far, but I'm not sure how to do this question since both values in the brackets have x in them.

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5 years ago
#2
(Original post by JustJusty)
"Find the value of the term in the expansion of (x-(1/x))^8 which is independent of x."

I've been using the nCr function and it worked great so far, but I'm not sure how to do this question since both values in the brackets have x in them.

The rth term of this expansion is going to be

So this term will be independent of when the exponent of becomes 0. For what value of is this?
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