MATLAB: How can we implement

Question

y(n)=(1/2)*(x(n)*A(1)+y(n-1)*A(2)-y(n-2)*A(3)+y(n-3)*A(4)-y(n-4)*A(5));

n=1:200

Answer 1

A=[ 1 2 3 4 5]
D=[1 A(2)  -A(3) A(4) -A(5)]
N=A(1)/2
x=ones(1,200)  % your input signal
y=filter(N,D,x)
stem(y)