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1. Binomial + Sequences
Hiya TSR people
Binomial problem:
3i) Find and simplify the first four terms in the binomial expansion of:

Did this bit fine.

ii)Hence find the coefficient of of:

what I did which is wrong is:

which is then 100.

How am I meant to do this?

Sequences help:

A sequence U1 u2 u3 is defined by Un=5n+1
Another sequence W1 w2 w3 is defined by W1=2 and Wn+1=5Wn+1

find the value of p so that
Up=W3

how do I find p? I don't know where to start.

stuff in size one font is meant to be subscript but I can't find the command for it.

2. Re: Binomial + Sequences
4*11.25 isn't 5
I also don't know why you're doing 4.44*3, it should be 15*3.
3. Re: Binomial + Sequences
(Original post by Stickyelmo)
Hiya TSR people
Binomial problem:
3i) Find and simplify the first four terms in the binomial expansion of:

Did this bit fine.

ii)Hence find the coefficient of of:

what I did which is wrong is:

which is then 100.

How am I meant to do this?

Sequences help:

A sequence U1 u2 u3 is defined by Un=5n+1
Another sequence W1 w2 w3 is defined by W1=2 and Wn+1=5Wn+1

find the value of p so that
Up=W3

how do I find p? I don't know where to start.

stuff in size one font is meant to be subscript but I can't find the command for it.

For the first one;

where did come from? it should be

Also

so summing up

For the second;

now

So set and sub in the expressions for both to find p.
Last edited by The Mr Z; 11-05-2012 at 11:47.
4. Re: Binomial + Sequences
Hmm I don't know where Im getting these random numbers. Thanks for the first one guys

how is Up=5p+1?
5. Re: Binomial + Sequences
(Original post by Stickyelmo)
Hiya TSR people
Binomial problem:
3i) Find and simplify the first four terms in the binomial expansion of:

Did this bit fine.

ii)Hence find the coefficient of of:

what I did which is wrong is:

which is then 100.

How am I meant to do this?

Sequences help:

A sequence U1 u2 u3 is defined by Un=5n+1
Another sequence W1 w2 w3 is defined by W1=2 and Wn+1=5Wn+1

find the value of p so that
Up=W3

how do I find p? I don't know where to start.

stuff in size one font is meant to be subscript but I can't find the command for it.

As slumpy says you have some pretty odd calculations. First 4*11.25 needs checking and where did the calculation below that come from?
6. Re: Binomial + Sequences
I'm not really sure about the numbers but recently I've been pressed wrong buttons on the calculator which isn't helping much
7. Re: Binomial + Sequences
(Original post by Stickyelmo)
how is Up=5p+1?
"A sequence U1 u2 u3 is defined by Un=5n+1"
8. Re: Binomial + Sequences
ooh okay I see it, thanks