% pseudospectra for Chebyshev differentiation matrices. 
% the matirces are generated using Trefethens cheb.m

N=8;
[D,x]=cheb(8);
A8=N^-2*D;
XX=N^-2*D(2:N+1,2:N+1);
N=24;
[D,x]=cheb(24);
A24=N^-2*D;
YY=N^-2*D(2:N+1,2:N+1);