x Turn on thread page Beta
 You are Here: Home >< Maths

# Can someone tell me where I went wrong? watch

1. On the attached image.
Attached Images

2. (Original post by EricPiphany)
On the attached image.
3. (Original post by TeeEm)
I've taken the second derivative of the first line, then substituted x = -1. For odd n, the left side is an integer and the right side is a fraction.
4. (Original post by EricPiphany)
I've taken the second derivative of the first line, then substituted x = -1. For odd n, the left side is an integer and the right side is a fraction.
hopefully one of the big guns will soon arrive
5. The mistake is your factorisation on the second line after subbing in x=-1.

You can't factorise (-1)n out of the entire numerator because of the +2 at the end.
6. (Original post by justinawe)
The mistake is your factorisation on the second line after subbing in x=-1.

You can't factorise (-1)n out of the entire numerator because of the +2 at the end.
An American comes to the rescue ...
7. (Original post by justinawe)
The mistake is your factorisation on the second line after subbing in x=-1.

You can't factorise (-1)n out of the entire numerator because of the +2 at the end.
Thanks a lot for that
8. I was much too eager to factorise that out...

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: November 4, 2015
Today on TSR

### How much will your degree earn you?

Find out where yours ranks...

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams