Laplace Transform of an Exponential Function in Matlab - matlab

Good day!
I hope anyone here knows MATLAB. I'm very new to it and I was just doing a practice. Anyways, I'm having trouble plotting the function in 2D and 3D of my exponential Laplace transform. Here's my code so far.
close all
clc
syms t;
u = input("Enter u: ");
a = input("Enter alpha: ");
f = u*exp(a*t);
F = laplace(f);
disp("The Laplace version")
disp(F)
t = 0:5:5;
p = subs(F);
plot(t,p)
Thanks for your help, in advance.

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Thanks in advance.
As pointed out by Cris Luengo in his comment my mistake was the usage of fftshift before computing the dct coefficients as I didn't take the shift position.

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check conv2 and fspecial in matlab help

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There's your google query :)