You are Here: Home >< Maths

# C 4 binomial expansion Watch

1. I know how to do the simple binomial expansions, but how would I do something like
3/2-x. Or 1/(1+x)^2
I understand that the power will be negative by what do I do with the number above? E.g the 3 in the first example.
2. (Original post by eggfriedrice)
I know how to do the simple binomial expansions, but how would I do something like
3/2-x. Or 1/(1+x)^2
I understand that the power will be negative by what do I do with the number above? E.g the 3 in the first example.
In the first case multiply the expansion by three - the expansion ought to be completed in the usual manner, so you need to get it in the form (1 + x)^n
In the second, nothing.
Do you see why?

3. (Original post by eggfriedrice)
I know how to do the simple binomial expansions, but how would I do something like
3/2-x. Or 1/(1+x)^2
I understand that the power will be negative by what do I do with the number above? E.g the 3 in the first example.
so you would get 3(2-x)^-1 but you have to take the 2 out because it must be in the form 1+ax so get 3*1/2(1-x/2) in the second one you simply do (1+x)^-2 and it is multiplied by 1 so it makes no difference.
4. Thanks, I get that now. Another thing I don't understand it's since the power is negative, then what's the sequence number? Like 5 is 1 5 10 10 5 1, but I don't know how to do it for a negative number ):
5. (Original post by eggfriedrice)
Thanks, I get that now. Another thing I don't understand it's since the power is negative, then what's the sequence number? Like 5 is 1 5 10 10 5 1, but I don't know how to do it for a negative number ):
You don't do that. Use the expansion provided in your textbook and formula book.
6. (Original post by Mr M)
You don't do that. Use the expansion provided in your textbook and formula book.
Kay thanks, got it!

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: April 3, 2013
Today on TSR

What should I do?

### How to go from a 4 to a 9 in GCSE Maths?

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE