I have this integral:
$$\int{\frac{x}{1+x^4}\ dx}$$
The solution should be:
$$\frac{1}{2} \arctan{x^2}+C$$
But I have only seen how to integrate when in denominator I have an expression with real roots. Here, with $1+x^4$ I dont have any real roots and I don't know how I can integrate it.