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# Maths as level help please

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1. How would you solve the q:
Find the x^5 term in the expansion of (x +2/x)^9

Any help is greatly appreciated ))
2. Do you know how to use binomial expansion? If so, use binomial expansion to expand that up until you get a term with x^5 in it, and then you have your answer. To answer this question you're needing knowledge of the binomial expansion - if you do not have this I'd highly recommend learning it as it always comes up in AS C2 past papers. You could, in hindsight, multiply that all out manually - however this will take a very long time and is extremely inefficient, and in an examination, if prompted to use binomial expansion, would score no marks.

Let me know how you get on with this

Edit: Also, Zacken could you move this to the Maths section please mate, as I think this may have been put in the A-level section by accident (or the OP could not locate the Maths section where he will get a lot more help!)
3. (Original post by Bubbly_yus)
How would you solve the q:
Find the x^5 term in the expansion of (x +2/x)^9

Any help is greatly appreciated ))
Do you mean the coefficient of the term? Think about which terms contribute to give a .

Try and post your mathematical queries in the maths forum in the future, I've moved it for you this time.

(Original post by iMacJack)
Edit: Also, Zacken could you move this to the Maths section please mate, as I think this may have been put in the A-level section by accident (or the OP could not locate the Maths section where he will get a lot more help!)
Thanks for the tag, appreciated - moved to maths
4. (Original post by Bubbly_yus)
How would you solve the q:
Find the x^5 term in the expansion of (x +2/x)^9

Any help is greatly appreciated ))
the general term is 9Cr*x^(9-r)*(2/x)^r = 9Cr * 2^r * x^(9-r) * x^(-r) = 9Cr * 2^r * x^(9-2r).
Thus to get x^5, we set r=2, giving a coefficient of 9C2 * 2^2 = 144.

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