% The function builds the matrix of basis Cheby I in x, given n

function P = Base_ChebyX(n,x)
%%
x = x(:); N = n+1;
P=zeros(length(x),N);

P(:,1)=1;    P(:,2)=x;
    
    for k=2:n
        P(:,k+1)= 2*x.*P(:,k)-P(:,k-1);
    end
%%