$$I=e^{x}; (\frac{1}{x}-\frac{1}{x^{2}})$$
$x=\ln(I)$
$\left(I=e^{-\frac{\sqrt{1-4a}-1}{2a}}\text{ and }a<0\right)\text{ or }\left(I=e^{-\frac{\sqrt{1-4a}-1}{2a}}\text{ and }a\leq \frac{1}{4}\text{ and }a>0\right)\text{ or }\left(I=e^{\frac{\sqrt{1-4a}+1}{2a}}\text{ and }a<0\right)\text{ or }\left(I=e^{\frac{\sqrt{1-4a}+1}{2a}}\text{ and }a\leq \frac{1}{4}\text{ and }a>0\right)\text{ or }\left(I=e\text{ and }a=0\right)$
