I just lost a huge page of LaTex.
Anyway I'll give you the abridged version.
I will expand on it if you need me too.
I split the numerator up to give me 3 seperate fractions to integrate.
$$\\\int \frac{x}{x+x^3}=\int \frac{1}{1+x^2}=atan(x)\\\\
\frac{7}{x+x^3} $ can be broken up using partial fractions into$\\\\\
\frac{7}{x}+\frac{-7x}{1+x^2}\qquad $ I can expand on this if you need me too$\\\\
$so our integral becomes$\\\\
\int\;\frac{7}{x}+\frac{-7x}{1+x^2}+\frac{1}{1+x^2}+\frac{3x}{1+x^2}\;dx\\\\
=\int\;\frac{7}{x}+\frac{-4x}{1+x^2}+\frac{1}{1+x^2}\;dx\\\\
=7ln(x)-2ln(1+x^2)+tan^{-1}(x)+c$$
I think that is correct.
I just lost a huge page of LaTex.
Anyway I'll give you the abridged version.
I will expand on it if you need me too.
I split the numerator up to give me 3 seperate fractions to integrate.
$$\\\int \frac{x}{x+x^3}=\int \frac{1}{1+x^2}=atan(x)\\\\
\frac{7}{x+x^3} $ can be broken up using partial fractions into$\\\\\
\frac{7}{x}+\frac{-7x}{1+x^2}\qquad $ I can expand on this if you need me too$\\\\
$so our integral becomes$\\\\
\int\;\frac{7}{x}+\frac{-7x}{1+x^2}+\frac{1}{1+x^2}+\frac{3x}{1+x^2}\;dx\\\\
=\int\;\frac{7}{x}+\frac{-4x}{1+x^2}+\frac{1}{1+x^2}\;dx\\\\
=7ln(x)-2ln(1+x^2)+tan^{-1}(x)+c$$
I think that is correct.