How to adapt code to apply a sine wave input instead

i am trying to turn the following code from step input into sine wave and dont know where to start. any help would be greatly appreciated.

t = 0:0.01:500;
u = ones(size(t)); 
u(1:100) = zeros(1,100); 
y = eval_system(u, t); 

Unrecognized function or variable 'eval_system'.

figure
plot(sin*t, u,'linewidth',2) 
hold on
plot(sin*t, y, 'linewidth',2)
grid on 

Answer 1

[Sulaymon Eshkabilov]

If undrestood correctly, you are trying to simulate the linear system. It can be attained using lsim(), e.g.:

t = 0:0.01:10;
y=sin(t);
U_SYS = tf(1, [1 2 3]);  % The given continuous system
OUT =  lsim(U_SYS,y,t);
figure
plot(t, y,'linewidth',2) 
hold on
plot(t, OUT, 'linewidth',2)
grid on 
legend('Input', 'Response')
xlabel('t, [s]')
ylabel('y(t), Out(t)')