I'm trying to plot the inverse Laplace transform of

>>syms s
>>Ys3 = (80000*s^2 + 400000*s)/(s^5 + 30*s^4 + 395300*s^3 + 11850000*s^2 + 202500000*s);

So I take this function and calculate its inverse laplace transform and I get this,

>>yt3 = ilaplace(Ys3);
>>yt3 = sum((400000*exp(r3*t) + 80000*r3*exp(r3*t))/(4*r3^3 + 90*r3^2 + 790600*r3 + 11850000), r3 in RootOf(s3^4 + 30*s3^3 + 395300*s3^2 + 11850000*s3 + 202500000, s3))

Needless to say, I'm stumped as to how I can graph this using the plot function. Because I don't know how to express the above result into something I can plot. Thus my dilemma.

Anyone knows how to get around this?

Thanks.

 

I would do this:
yt3=ilaplace(Ys3);
t=0:0.001:2;
plot(t, yt3);

 

It's what I tried, but ilaplace(Ys3) outputs a symbolic expression. I'm not sure how MATLAB can recognize the "sum((400000...)) r3 in RootOf(...)" as a vectorized solution.

Has me really stumped.

 

I am not sure where you get r3. Have you looked at this yet: http://www.mathworks.com/help/toolbox/symbolic/ilaplace.html