MATLAB: (input given as ?[?] = {1, 2,3} impulse given as ℎ[?] = {4,5,6} for 0 ≤ ? ≤ 2.) there is an error in the output..in sketching of y[n], we required a discrete in time signal but the output signal is continuous as seen clearly in screenshot below

n = 0:2; x =[1 2 3]; h=[4 5 6]; y=conv(x,h);

plot(y) xlabel('time axis'); title('output of a system'); ylabel('y axis')

stem(y);

%true
for i = 1: 6
 subplot(6,2,i)
 y = cos(i*x);
 plot(x,y)
 title(sprintf('y = cos(%dx)', i));
end

x = [1,2,3,4,5,6,4,2,7,5,3]
y=[x;x]
y=y(:)'

%Or

n=2
x=repmat(x,n,1);
y=y(:)'