I am trying to convolve two functions:
$f(t) = e^{- t}$
$g(t) = e^{-(e^{-t})^2}$
$(f*g)(t) = \int_{0}^{t} f(t-\tau)g(\tau) d\tau = \int_{0}^{t} e^{-(t-\tau)} e^{-(e^{-\tau})^2} d\tau$
Using the convolution property, we can transform it into a product of folding functions, each of which is obtained using the direct Laplace transform of each of the original functions, i.e.:
$(f*g)(t) \rightarrow L^{-1}(L(f(t)) \cdot L(g(t)))$
But it is known that the original functions must meet certain requirements.
With these functions, the Laplace transform will look like:
ut = Exp[-Exp[-t]^2]
LaplaceTransform[ut, t, s] LaplaceTransform[Exp[-t], t, s]
And this is result:
$\frac{\Gamma \left(\frac{s}{2}\right)-\Gamma \left(\frac{s}{2},1\right)}{2 s+2}$
InverseLaplaceTransform[(Gamma[s/2] - Gamma[s/2, 1])/(
2 + 2 s), s, t]
Out[85]= InverseLaplaceTransform[(Gamma[s/2] - Gamma[s/2, 1])/(
2 + 2 s), s, t]
But the inverse Laplace transform of this function does not work. What could be the reason and are there any ways to find the inverse Laplace transform of this function?
I will be glad to any advice and help.
Integrategives the result within 2 seconds, how do you code it?:f[t_] = E^-t; g[t_] = Exp[-Exp[-t]^2]; AbsoluteTiming[Integrate[f[t - \[Tau]] g[\[Tau]], {\[Tau], 0, t}]]– xzczd Jul 04 '20 at 07:41Exp[-2 t]– dtn Jul 04 '20 at 07:47f2[t_] = InverseLaplaceTransform[-Gamma[s/2, 1], s, t]; g2[t_] = InverseLaplaceTransform[1/(2 s + 2), s, t]; Integrate[f2[t - \[Tau]]*g2[\[Tau]], {\[Tau], 0, t}] // FullSimplify– Mariusz Iwaniuk Jul 04 '20 at 10:50