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# C4 Binomial Expansion watch

1. I've done the first part of the question but can't figure out the second part.

Q - Hence, or otherwise, find the first 3 terms in the expansion of (x + 8) / sqroot(4 - 3x) as a series in ascending powers of x

From part a I expanded sqroot(4 - 3x) to:

1/2 + 3x/16 + 27x^2/256

I'm unsure on what I do with the (x + 8)

I tried expanding it and got:

8^1(1 + x/8)^1 however on the 3rd term n-1 would equal 0 so I'm not sure how I expand (x + 8) if that's what I need to do.

All help much appreciated
2. Urm... when you expand you get But this isn't your problem.

You can re-write your expression as , which in turn is equal to .

What you need to do is expand (the first 3 terms will do), and then multiply the result by . And then multiply that by .
3. Aha I see, thanks!
Yeah the first part was 1 / sqroot(4-3x). forgot to say that

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