%ex1
N=100;
x=[zeros(1,N/2) ones(1,N/2)]; #semnal treapta unitate
figure
stem(x)

for n = 1:N
  for k = 2:n
    y(n) = x(k) - x(k-1); %DERIVATOR DE ORDINUL 1
end
end

figure
stem(y)