[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:

the answer is actually

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.






Thanks in advance

[Slumpy]

4*11.25 isn't 5
I also don't know why you're doing 4.44*3, it should be 15*3.

[The Mr Z]

(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:

the answer is actually

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.






Thanks in advance

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.

[Stickyelmo]

Hmm I don't know where Im getting these random numbers. Thanks for the first one guys

how is Up=5p+1?

[Intriguing Alias]

(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:

the answer is actually

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.






Thanks in advance

As slumpy says you have some pretty odd calculations. First 4*11.25 needs checking and where did the calculation below that come from?

[Stickyelmo]

I'm not really sure about the numbers but recently I've been pressed wrong buttons on the calculator which isn't helping much

[Intriguing Alias]

(Original post by Stickyelmo)
how is Up=5p+1?

"A sequence U1 u2 u3 is defined by Un=5n+1"

[Stickyelmo]

ooh okay I see it, thanks