error in plotting graph

function homework
clc
clear all
global A B C L x0 tspan 
A = [0 1;0 0];
B = [0;1];
C = [1 0];
L = [1.8750;2.6250];
tspan = [0:.1:10];
x0 = [1 0];
[x,y] = solbasic
z0 = [10 11]
z(1,:)=[10 11];
z1=z(1,:); %gives the first row
z2=z1
for i = 1:100;
t_temp =((i-1)/10):.05:(i/10);
[~,z]=ode45(@observer,t_temp,z(end,:))
z1=[z1;z(end,:)]
z2=[z2;z(2,:);z(end,:)]
end
function dzdt = observer(t,z); 
dzdt=(A-L*C)*z+L*[(y(i,:)+y(i+1,:))/2]'+B*[t^2];
end
y_cap = z1*C';
e=x-z1;
figure(1)
plot(tspan,x(:,1),'r',tspan,y_cap(:,1),'b--','LineWidth',2.5)
xlabel({'Time t';'(a)'}, 'FontWeight','b','FontSize',14)
ylabel('First State', 'FontWeight','b','FontSize',14)
leg1 =legend('True x(1)','Estimated x(1)')
set(leg1,'FontSize',16);
figure(2)
plot(tspan,x(:,2),'r',tspan,y_cap(:,2),'b--','LineWidth',2.5)
xlabel({'Time t';'(b)'}, 'FontWeight','b','FontSize',14)
ylabel('Second State', 'FontWeight','b','FontSize',14)
leg2=legend('True x(2)','Estimated x(2)')
set(leg2,'FontSize',16);
end
function [x y] = solbasic()
global A B C x0 tspan u
[~, x] = ode45(@basic, tspan, x0)
y=x*C'
end
function dxdt = basic(t,x)
A = [0 1;0 0];
B = [0;1];
dxdt=A*x+B*[t^2]
end

Error that i am having is-

Index in position 2 exceeds array bounds (must not exceed 1).

Error in homework (line 38)

plot(tspan,x(:,2),'r',tspan,y_cap(:,2),'b--','LineWidth',2.5)

Answer 1

[KSSV]

Replace the line:

plot(tspan,x(:,2),'r',tspan,y_cap(:,2),'b--','LineWidth',2.5)

with

plot(tspan,x(:,2),'r',tspan,y_cap,'b--','LineWidth',2.5)

[Meenakshi Tripathi]

Thank you!!!

could you please explain why you did this? Also when i did the same , my graph is not converging. what should be done in that case?

are you aware of simulation of observer design related problem?

[KSSV]

Check the dimensions of each input you have given to plot. The dimensions of y_cap is 101X1, so you cannot use y_cap(:,2).