Couldn't think of a title, as i'll be using this thread more than once today for related, but different problems.
For this, I ended up with -2sinxcosx, it's supposedly wrong.
Here's my work, for reference:
Thanks in advance/
in the previous picture, i accidentally left out the -sinxcosx next to the fraction which would combine with the -sinxcosx that would be left after the 1+cos2x's cancelled out.
I've since figured this out (the question was to simplify as far as possible, by the way. sorry about that.). It's tanx.