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# C2 Binomial Expansion Question 2 watch

1. Okay, I'm really stuck on this question...

Find the first four terms in the expansion of (1 + x + x^2)^7 in ascending powers of x.

I understand you write it as [(1 + x) + x^2]^7...
However, I'm not too sure about what to do and hte methods that I have been using do not lead to the correct answer.

Thanks!
2. I would be surprised if this was C2.
3. You would do better to write it as [1+(x+x^2)]^7, or better yet [1+(x(1+x))]^7

Why? Because in those forms it is much easier to see which terms will be of order x^4 or higher, and therefore ignorable (since you are looking only for the first 4 terms).
4. (Original post by steve2005)
I would be surprised if this was C2.
It is but rarely comes up.
5. (Original post by mcp2)
It is but rarely comes up.
OK Thanks.

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Updated: August 2, 2009
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