I need help plotting this inverse Laplace Transform

I am trying to plot an inverse Laplace transform of a function but I keep getting the error "Error using plot. Data must be numeric, datetime, duration or an array convertible to double."

Below is my code:

m=1;
c=6;
k=6;
G = 100.*65.*9.81;

syms s pi t

f1=(1/((s^2+4*pi^2)*(m*s^2+c*s+k))); %first term
pf1=partfrac(f1,s);

f2=(1/(3*(s^2+(6*pi)^2)*(m*s^2+c*s+k))); %second term
pf2=partfrac(f2,s);

f3=(1/(5*(s^2+(10*pi)^2)*(m*s^2+c*s+k))); %third term
pf3=partfrac(f3,s);

f4=(1/(7*(s^2+(14*pi)^2)*(m*s^2+c*s+k))); %fourth term
pf4=partfrac(f4,s);

LF1=ilaplace(f1) %inverse laplace transform of first term

LF1 = 

LF2=ilaplace(f2) %inverse laplace transform of second term

LF2 = 

LF3=ilaplace(f3) %inverse laplace transform of third term

LF3 = 

LF4=ilaplace(f4) %inverse laplace transform of fourth term

LF4 = 

t = [0;0.1;10];

Xss = LF1 - LF2 + LF3 - LF4;

plot(t,Xss)

Error using plot
Data must be numeric, datetime, duration or an array convertible to double.

[Torsten]

Xss = LF1 - LF2 + LF3 - LF4;
t_num = 0:0.1:10;
Xss_num = double(subs(Xss,t,t_num));
plot(t_num,Xss_num)

[Caleb Truscott]

Hi, I tried this but I get:

m=1;
c=6;
k=6;
G = 100.*65.*9.81;

syms s pi t

f1=(1/((s^2+4*pi^2)*(m*s^2+c*s+k))); %first term
pf1=partfrac(f1,s);

f2=(1/(3*(s^2+(6*pi)^2)*(m*s^2+c*s+k))); %second term
pf2=partfrac(f2,s);

f3=(1/(5*(s^2+(10*pi)^2)*(m*s^2+c*s+k))); %third term
pf3=partfrac(f3,s);

f4=(1/(7*(s^2+(14*pi)^2)*(m*s^2+c*s+k))); %fourth term
pf4=partfrac(f4,s);

LF1=ilaplace(f1) %inverse laplace transform of first term

LF1 = 

LF2=ilaplace(f2) %inverse laplace transform of second term

LF2 = 

LF3=ilaplace(f3) %inverse laplace transform of third term

LF3 = 

LF4=ilaplace(f4) %inverse laplace transform of fourth term

LF4 = 

t = 0:0.1:10;

Xss = LF1 - LF2 + LF3 - LF4;
t_num = 0:0.1:10;
Xss_num = subs(Xss,t,t_num);

Error using sym/subs>normalize (line 239)
Entries in second argument must be scalar.

Error in sym/subs>mupadsubs (line 165)
[X2,Y2,symX,symY] = normalize(X,Y); %#ok

Error in sym/subs (line 153)
G = mupadsubs(F,X,Y);

plot(t_num,Xss_num)

[Paul]

Don't use a sym variable name pi. Better is to use a sym constant, i.e., replace all uses of pi with

Pi = sym(pi);

comment out this line:

% t = 0:.1:10

Answer 1

[Paul]

Replace all instances of pi with Pi, defined as

Pi = sym(pi);

which is a good habit to get into regardless.

Then you can stay in the sym world if you want and use fplot()

fplot(Xss,[0 10])

[Caleb Truscott]

Hi thank you it works:

m=1;
c=6;
k=6;
G = 100.*65.*9.81;
Pi = sym(pi);

syms s pi t

f1=(1/((s^2+4*Pi^2)*(m*s^2+c*s+k))); %first term
pf1=partfrac(f1,s);

f2=(1/(3*(s^2+(6*Pi)^2)*(m*s^2+c*s+k))); %second term
pf2=partfrac(f2,s);

f3=(1/(5*(s^2+(10*Pi)^2)*(m*s^2+c*s+k))); %third term
pf3=partfrac(f3,s);

f4=(1/(7*(s^2+(14*Pi)^2)*(m*s^2+c*s+k))); %fourth term
pf4=partfrac(f4,s);

x1=ilaplace(f1) %inverse laplace transform of first term

x1 = 

x2=ilaplace(f2) %inverse laplace transform of second term

x2 = 

x3=ilaplace(f3) %inverse laplace transform of third term

x3 = 

x4=ilaplace(f4) %inverse laplace transform of fourth term

x4 = 

%t = 0:0.1:10

Xss = x1 - x2 + x3 - x4;

fplot(Xss,[0 10])
xlabel('Time (s)')
ylabel('x (m)')
legend('Xss(t)')
title('Lateral Displacement')