It seems there should be an easy way to compute this, but I do it by hand everytime. What tool can I use?

Let: $v(t) = 8 e^{-t} \cos t \mathrm{~Volts}$

I want to find the complex frequency s given $s=\sigma+j \omega$ and the general forcing function: $v(t)=V_{m} e^{\sigma t} \cos (\omega t+\theta)$

so in this case the answer is: $S=-1+j$

I'm very new to circuit analysis. I want to get faster and I like scripting