Year 12s: what will be the first way you research your future options? >>

tough binomial function question!! help!!

bored_user:)

There's the question.

Scroll to see replies

part 2 pls

Original post by bored_user:)

part 2 pls

The binomial coeffs are an expansion of
(1+x)^n
When x=1

(edited 3 years ago)

Reply 3

bored_user:)

Original post by mqb2766

The binomial covers are an expansion of
(1+x)^n
When x=1

So do I write (1+x)^n = 2^n

and then sent x=1?

Reply 4

RDKGames

Study Forum Helper

Original post by bored_user:)

So do I write (1+x)^n = 2^n

and then sent x=1?

No.

Firstly, can you represent

(1+x)^n

as a sum of increasing powers of

x

using the binomial theorem?

Then substitute

x=1

into both sides of this relation.

Result falls out.

Reply 5

mqb2766

Expand (1+x)^n
Then set x=1 in both the expansion and the original expression.

Reply 6

bored_user:)

Original post by RDKGames

No.

Firstly, can you represent

(1+x)^n

as a sum of increasing powers of

x

using the binomial theorem?

Then substitute

x=1

into both sides of this relation.

Result falls out.

So is this the answer?

image-98e06cfd-5ee0-447d-9294-3943746bdea33349879676836789606-compressed.jpg.jpeg

Reply 7

bored_user:)

Original post by mqb2766

Expand (1+x)^n
Then set x=1 in both the expansion and the original expression.

How do I even expand that when n has no value??

Reply 8

mqb2766

Original post by bored_user:)

So is this the answer?

image-98e06cfd-5ee0-447d-9294-3943746bdea33349879676836789606-compressed.jpg.jpeg

Are you actually setting x=1 in the expansion of the binomial?

Reply 9

RDKGames

Study Forum Helper

Original post by bored_user:)

So is this the answer?

Almost.

Is

\displaystyle \sum_{k=0}^n \binom{n}{k}

really the series expansion of

(1+x)^n

Reply 10

mqb2766

Original post by mqb2766

Are you actually setting x=1 in the expansion of the binomial?

(1+x)^n = 1+nx + n(n-1)/2x^2 + ... + x^n
When x=1, the right equals ?

(edited 3 years ago)

Reply 11

bored_user:)

Original post by RDKGames

Almost.

Is

\displaystyle \sum_{k=0}^n \binom{n}{k}

really the series expansion of

(1+x)^n

I have no idea what's going on here...

Can you tell me what the correct answer is and explain it please? Thanks

Reply 12

RDKGames

Study Forum Helper

TBH, you should've come across the binomial theorem (which is also in the Edexcel formula booklet!) when it tells you that

(a+b)^n = \displaystyle \sum_{k=0}^n \binom{n}{k}a^kb^{n-k}

Choosing appropriate values for

a,b

makes the answer fall out immediately.

Reply 13

mqb2766

Original post by bored_user:)

I have no idea what's going on here...

Can you tell me what the correct answer is and explain it please? Thanks

What is the binomial expansion of
(1+x)^n

Reply 14

bored_user:)

Original post by mqb2766

(1+x)^n = 1+nx + n(n-1)/2x^2 + ... + x^n
When x=1, the right equals ?

is this it?
image-446e6ae6-1821-4c49-8b3a-5935681a8e924826274400607781229-compressed.jpg.jpeg

Reply 15

mqb2766

Original post by bored_user:)

is this it?
image-446e6ae6-1821-4c49-8b3a-5935681a8e924826274400607781229-compressed.jpg.jpeg

Yes. The rows in Pascal triangle sum to 2^n.

Reply 16

bored_user:)

Original post by mqb2766

Yes

Omg thank you so much for helping!!!

Reply 17

jellybellyb

Yep, super tough.

@Rufus the red
@nikkiblonsky

Reply 18

bored_user:)

Original post by jellybellyb

Yep, super tough.

@Rufus the red
@nikkiblonsky

This is uni stuff lol.

Reply 19

Rufus The Red

Original post by jellybellyb

Yep, super tough.

@Rufus the red
@nikkiblonsky

Sorry about this fool.

Quick Reply

Related discussions

Latest

Articles for you

Don't make these mistakes when you're choosing a university

Writing a law personal statement: expert advice from universities

How to get a pupillage (and what to do if you don’t get one)

Students who got grade 9s at GCSEs share study tips that everyone can follow

tough binomial function question!! help!!

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you