Let

A=

Attachment 23301

Pick out the smallest disc (and explain why ) in the complex plane containing all the eigenvalues

of A from amongst the following:

a. |z - 1|<= 7;

b. |z - 1|<= 6;

c. |z - 1|<=4.

P.S: i know gershgorin theorem.but how to find the smallest circle? confused.

Thanks in advance.Regards(Itwasntme)