x=[1 -1 0 2 4 -3];
norm(x,1)

norm(x,2)

norm(x,inf)

A=[-1 2 3; 0 1 -1; 2 -3 5];
norm(A,1)

norm(A,2)

norm(A,inf)

norm(A,2)/norm(A,1)

A=[-1 2 3; 0 1 -1; 2 -3 5];
B=[0 2 -1; 3 6 -2; 8 5 1];
x=[1 -1 0]';
norm(A*B) <= norm(A)*norm(B)

norm(A*x,1) <= norm(A,1)*norm(x,1)

A=[-4 11 3; 7 2 -1; 13 0 6];
cond_1=norm(A,1)*norm(inv(A),1)

cond_inf=norm(A,inf)*norm(inv(A),inf)

cond_2=norm(A,2)*norm(inv(A),2)

cond(A)

H2=hilb(2)

H3=hilb(3)

inv(H2)

inv(H3)

b=[1.767 1.167 0.912 0.758 0.652]';
A=hilb(5);
x=A\b

bhat=[1.77 1.17 0.91 0.76 0.65]';
A=hilb(5);
xhat=A\bhat


