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C2 Binomal Expansion - Sixth form

Please can someone help me with this question. I have no clue on how to answer it.

Thank you in advance



maths problem.png
Reply 1
Avatar for Notnek
Notnek
21
Original post by bigmansouf
Please can someone help me with this question. I have no clue on how to answer it.

Thank you in advance



maths problem.png

For a), first write out the expansion of (1+x)^n and then think about substitutions you could make for x.

Post any working/ideas you have if you're still stuck.
Reply 2
Avatar for bigmansouf
bigmansouf
OP
20
Please look at my work this is what I have done but still confused on what to do next Scan0087.jpg


Scan0086.jpg
Reply 3
Avatar for davros
davros
16
Original post by bigmansouf
Please look at my work this is what I have done but still confused on what to do next Scan0087.jpg


Scan0086.jpg


You're making life far too difficult for yourself!

What are the 2 simplest values for x you could choose?
Reply 4
Avatar for bigmansouf
bigmansouf
OP
20
you could choose x=1 or x=2
Reply 5
Avatar for davros
davros
16
Original post by bigmansouf
you could choose x=1 or x=2


Choosing x = 1 would give you (1+x)n=2n(1 + x)^n = 2^n which helps for the first part.

But choosing x = 2 gives (1+x)n=3n(1 + x)^n = 3^n, which isn't what you want.

What other value of x might you try?
Reply 6
Avatar for bigmansouf
bigmansouf
OP
20
choose x=1
i understand but im still confused about the expansion bit
Reply 7
Avatar for davros
davros
16
Original post by bigmansouf
choose x=1
i understand but im still confused about the expansion bit


Which one - the second one or both parts?

Presumably in class your teacher has gone through the expansion of (a+b)n(a + b)^n where n is a positive integer?
Reply 8
Avatar for bigmansouf
bigmansouf
OP
20
Original post by davros
Which one - the second one or both parts?

Presumably in class your teacher has gone through the expansion of (a+b)n(a + b)^n where n is a positive integer?


Sorry i have been learning it myself the whole alevel due to unfortunate circumstances i have to learn by myself

I have purchase a dvd from http://s256376672.websitehome.co.uk/mathstutor.html
and m4ths.com


i have gone all the questions from the main edexcel c2 book but this question is the further extension question from Rosemary's Edexcel as Core Mathematics

http://www.amazon.co.uk/Core-Mathematics-Edexcel-LEVEL-MATHS/dp/0582842379/ref=sr_1_1?s=books&ie=UTF8&qid=1429715259&sr=1-1&keywords=rosemary+edexcel

this is the only question i have yet to overcome 55-14ext-14.pdf
(edited 9 years ago)
Reply 9
Avatar for davros
davros
16
, so
Original post by bigmansouf
Sorry i have been learning it myself the whole alevel due to unfortunate circumstances i have to learn by myself

I have purchase a dvd from http://s256376672.websitehome.co.uk/mathstutor.html
and m4ths.com


i have gone all the questions from the main edexcel c2 book but this question is the further extension question from Rosemary's Edexcel as Core Mathematics

http://www.amazon.co.uk/Core-Mathematics-Edexcel-LEVEL-MATHS/dp/0582842379/ref=sr_1_1?s=books&ie=UTF8&qid=1429715259&sr=1-1&keywords=rosemary+edexcel


OK, so have you seen the formula for expanding (a+b)n(a + b)^n in terms of binomial coefficients?
yh i have seen it and applied it to understand the subject but somehow I dont understand this question
I will revise this topic and revise the question

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