% Spectral Derivative for a Cheby's serie Type I

function D = D_Cheb_A(n)

%% Matrix of differentiation

%% By the Z matrix
Z = zeros(n+1,n+1);
Z(2,1) = 1; Z(3,2) = 4;
%%
for k = 2:n-1
    Z(k+2,k+1) = 2*(k+1);
    Z(k+2,:) = Z(k+2,:) + (k+1)*Z(k,:)/(k-1);
end

D = Z.';