Yes I'm still at integration lol but this is the last question for the book so anyway the question's:

The indefinite integral (integrate) [P(x)/(x^3 + 1)] dx, where P(x) is a polynomial in x, is denoted by I.

(i) Find I when P(x) = x^2. (Answer: 1/3 ln | x^3 + 1 | + C)

(ii) By writing x^3 + 1 = (x + 1)(x^2 + Ax + B), where A and B are constants, find I when

(a) P(x) = x^2 - x + 1, (Answer: ln | x + 1 | + C)

(b) P(x) = x + 1 (Answer: 2/(sq root 3) tan^-1 2/(sq root 3) (x - 1/2) + C)

(iii) Using the results of parts (i) and (ii), or otherwise, find I when P(x) = 1. (Answer: 1/3 ln | x + 1 | + 1/6 ln | x^2 - x + 1 | + 1/(sq root 3) tan^-1 2/(sq root 3) (x - 1/2) + C)

I got the answers for all except the last part (iii).

So thanks if anyone could help!