How would you solve the q:
Find the x^5 term in the expansion of (x +2/x)^9
Any help is greatly appreciated ))
Maths as level help please Watch
- Thread Starter
- 11-04-2016 16:39
- 11-04-2016 18:23
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!)Last edited by iMacJack; 11-04-2016 at 18:24. Reason: Request to move.
- 11-04-2016 18:28
- 12-04-2016 07:10
Thus to get x^5, we set r=2, giving a coefficient of 9C2 * 2^2 = 144.