||'''Book'''|| Advanced Engineering Mathematics ||
 ||'''Author'''|| Erwin Kreyszig ||
 ||'''Edition'''|| 8th Edition ||

/* code_begins */

{{{

a,k = var('a,k')

A = matrix([[a,k,k],[k,a,k],[k,k,a]])

print A

A.characteristic_polynomial()

A.eigenvalues()

# all the eigenvalues are real => the matrix is symmetric, if a, k are real.


}}}

/* code_ends */

 * '''Solution by''': 
  * ganesh, developer, space
  * bhanukiran, student, technical university of Delft
  * saransh, student, sobhit university
  * ujwala, lecturer, aurangabad