Your answer and the book's answer are the same! You just need to simplify to 3.
The problem wants me to use the quotient rule and this is the problem
d/dx 3x^2 + 3/ arctanx
I can get the answer worked out as far as
6xarctanx - (3x^2 + 3) ( 1 / (x^2 + 1) / arctan^2 x
but the final answer in the book is
6xarctanx - 3/ arctan^2 x
how does it go from what I have to what the final answer should be? I figure it something simple but I just am not seeing it.