I had this integral,
$$\int_0^{\infty} \frac{dx}{(x+5) \,(x^2 + 1)}$$ I simplified using partial fractions and eventually got to $$\lim_{t \rightarrow\infty} \frac{\ln(t+5)}{26}-\frac{\ln(t^2+1)}{52} +\frac{\ 5arctan(t)}{26} - \frac{\ln5}{26}$$
At this step, after plugging in infinity, I get $$ \infty - \infty \, + \frac{\pi}2- \frac{\ln 5}{26}$$
Clearly, in the form infinity - infinity, you cannot apply L'Hopital's Rule. Is there anyway to simplify this to $$\frac{\infty}{\infty}$$
so that the Rule can be applied?
Hint
$$\frac{\log(t+5)}{26}-\frac{\ln(t^2+1)}{52}=\frac 1{52}\left(\log((t+5)^2)-\log(t^2+1) \right)=\frac 1{52}\log\left(\frac{(t+5)^2}{t^2+1}\right)$$ could help