# need help expanding

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• Apr 30th 2008, 11:44 AM
cowboys111
need help expanding
Can someone please help me expand this, (x-2)^(k+1).
Thanks for the help
• Apr 30th 2008, 11:54 AM
flyingsquirrel
Hi

You can use the binomial theorem : $(a+b)^n=\sum_{i=0}^n\binom{n}{i}a^i\times b^{n-i}$
• Apr 30th 2008, 11:56 AM
topsquark
Quote:

Originally Posted by cowboys111
Can someone please help me expand this, (x-2)^(k+1).
Thanks for the help

$(a + b)^{m} = \sum_{i = 0}^m {m \choose {m - i}}a^{m - i}b^i$

So
$(x - 2)^{k+1} = \sum_{i = 0}^{k + 1} {{k + 1} \choose {k + 1 - i}}x^{k + 1 - i}(-2)^i$

-Dan