Why I cannot see any result on my graph

clc
clear all
sympref('FloatingPointOutput',true)

syms X(t)
syms S1(t)
syms S2(t)
syms B1(t)
x=1
L=1


t1=0
kd=0.076
Bmax=15.658
ib=0.616
K1=171.492
Umaxg=0.730
Ksg=1.293
Ksx=4.469
Umaxx=0.615
SG=31
SGn=SG %g/l

SX=32 %g/l
B=0 %g/l
x0=0.01 %g/l
Xn=x0 %g/l
Yxsg=0.523
Yxsx=0.058
Ybsg=1.196
Ybsx=0.232
Ybxg=Ybsg/Yxsg
Ybxx=Ybsx/Yxsx
Usg=(Umaxg*SG)/((Ksg+SG)*((1+SX)/Ksx))
Usx=(Umaxx*SX)/((Ksx+SX)*((1+SG)/Ksg))
Ug=(Usg+Usx)*(K1/(K1+SG+SX))*(1-(B/Bmax))^(ib)
Unet=Ug-kd
ode = diff(X,t)==Unet*X;
cond=X(t1)==Xn;
XSol(t)=dsolve(ode,cond)

ode = diff(S1,t)== -Usg*((1/Yxsg)+(1/Ybsg))*XSol;
cond= S1(t1)==SGn;
SGsol(t)=dsolve(ode,cond)

ode = diff(S2,t)== -Usx*((1/Yxsx)+(1/Ybsx))*XSol;
cond= S2(t1)==SGn;
SXsol(t)=dsolve(ode,cond)

ode = diff(B1,t)== (Usg*Ybxg+Usx*Ybxx)*XSol;
cond= B1(t1)==B
Bsol(t)=dsolve(ode,cond)

for i=0:10:300
XSol(i);
SGsol(i) ; 
SXsol(i);
Bsol(i);

end

plot(i,SXsol(i)) 

Answer 1

[Voss]

Instead of this:

plot(i,SXsol(i)) 

try this:

fplot(SXsol,[0 300])

or this:

t_plot = 0:10:300;
plot(t_plot,SXsol(t_plot))

[Berk Han]

Thank you!

fplot(SXsol,[0 300]) is working in my code.

[Voss]

You're welcome!

Answer 2

[Cris LaPierre]

By default, MATLAB plots using a solid line style with no marker. When you plot a single point like your code is doing, this results in your point not being visible.

If you truly want to plot the ith point, then add a marker style.

plot(i,SXsol(i),'o') 

If you instead want to plot all your data, remove i.

plot(SXsol) 

[Berk Han]

Thanks but plot(SXsol) didnt work.

[Cris LaPierre]

I overlooked that SXsol was a symfun. Use one of the solutions described by Voss.