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# C2 Binomial Expansion watch

1. Hi there,

I've never seen this type of question before and I am very confused...

So I know that nC0 = 1
and that nC1 = n

So I have 1 + n(x/4) as the first two terms

I have no idea where go from there - This topic was only recently taught and I'm not very good at it, so if anyone could provide a detailed explanation on how to tackle this question I would be most grateful.

Thanks
2. (Original post by CrazyFool229)
Hi there,

I've never seen this type of question before and I am very confused...

So I know that nC0 = 1
and that nC1 = n

So I have 1 + n(x/4) as the first two terms

I have no idea where go from there - This topic was only recently taught and I'm not very good at it, so if anyone could provide a detailed explanation on how to tackle this question I would be most grateful.

Thanks
Look in your formula booklet, you should see:

To expand your formula, just replace all the places where you see an with , so:

3. (Original post by Zacken)
Look in your formula booklet, you should see:

To expand your formula, just replace all the places where you see an with , so:

Wow, thanks again Zacken. Don't know what I would do without your wisdom.

So is there a chance of them asking to expand (2+X/4) then? Would the formula still apply? If so, would it be the same substitution?
4. (Original post by CrazyFool229)
Wow, thanks again Zacken. Don't know what I would do without your wisdom.

So is there a chance of them asking to expand (2+X/4) then? Would the formula still apply? If so, would it be the same substitution?
Not quite, the substitution only works with i.e: there needs to be a 1 in the first term of the bracket.

But there's a sneaky trick around this.

If you had - factor out a 2: .

Then you can just expand the latter fraction using the substitution of replacing wherever you see wuth and then multiply all the terms of your series by .

i.e:
5. (Original post by Zacken)
Not quite, the substitution only works with i.e: there needs to be a 1 in the first term of the bracket.

But there's a sneaky trick around this.

If you had - factor out a 2: .

Then you can just expand the latter fraction using the substitution of replacing wherever you see wuth and then multiply all the terms of your series by .

i.e:
Thanks again!
I would rep you but it isn't letting me
6. (Original post by CrazyFool229)
Thanks again!
I would rep you but it isn't letting me
7. (Original post by Zacken)
Look in your formula booklet, you should see:

To expand your formula, just replace all the places where you see an with , so:

Go to exam solutions
8. (Original post by Naughty1)
Go to exam solutions
Compelling.
9. (Original post by Zacken)
Not quite, the substitution only works with i.e: there needs to be a 1 in the first term of the bracket.

But there's a sneaky trick around this.

If you had - factor out a 2: .

Then you can just expand the latter fraction using the substitution of replacing wherever you see wuth and then multiply all the terms of your series by .

i.e:
shouldn't you be revising
10. (Original post by tinkerbella~)
shouldn't you be revising
That's for nerds.
11. (Original post by Zacken)
That's for nerds.
you are a nerd
12. (Original post by tinkerbella~)
you are a nerd
Yes he is
13. (Original post by tinkerbella~)
you are a nerd
Apparently not, since I'm not revising.
14. (Original post by Zacken)
Apparently not, since I'm not revising.
oh you got me there

(Original post by Pablo Picasso)
Yes he is
kinda cool for a nerd though
15. (Original post by tinkerbella~)
oh you got me there

kinda cool for a nerd though
'innit
16. Isnt this c4 not c2?
17. (Original post by Mitul106)
Isnt this c4 not c2?
Binomial expansion is C2 for Edexcel.

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