The problem is: $\displaystyle \int \frac{e^{3x}}{e^{6x}+1}$

By using multiple product rules, I ended up with $\displaystyle \frac{5^{2x}}{x}+2ln(5)ln(3x)$

The answer choice I selected had the same answer, except that it had $\displaystyle 5^{2x}$ at the end. $\displaystyle \frac{5^{2x}}{x}+2ln(5)ln(3x)5^{2x}$

Which one is correct? If it is the second one, can you please explain where the additional $\displaystyle 5^{2x}$ came from?