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# C1 Sequences and series watch

1. So my weakness, rearranging stuff comes back to haunt me again...
Q2 is : Find the value of n for which has the given value:
= , =

So from that, I have

=

and don't know where to go from there. I'm guessing it involves multiplying out the n+4 but don't really know
Help please, oh lovely mathemeticians? ty x
2. I've never seen C1 questions written in Latex before but I'm suitably impressed.

Notice you want to rewrite 7/9 in a form where the denominator is 4 greater than the numerator, i.e. write 7/9=14/18 which should make the answer clear.
3. That's a nice method from Gaz there, use that ^^^

Alternatively, you could do some basic case analysis. Firstly make the assumption that the value of n you're trying to find is even. See if that assumption leads to a solution, but remember you assumed n is even so the only valid solutions to this equation will be even. Then do exactly the same thing except assume that n is odd.

The idea is that by doing this you can get rid of the (-1)^n. If n is off then it's always equal to -1 whereas if n is even it's always equal to 1. In either case you should have a relatively easy equation to solve.

But like I say, Gaz's method is much nicer. Use that
4. Thanks for your help, but I'm afraid I don't get it, the dummy I am

So now I've got = n+4

I doubt that's right but if it is, I'm stuck again haha. Sorry :P
5. I think he meant that

You can just read off n from this. It's a clever trick but I think JohnnySPal's method is better for your knowledge.

*Edit*

If you're still not following then:

6. Ooo.. ty :]

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