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

/* code_begins */

{{{
A = matrix([[0,9,-12],[-9,0,20],[12,-20,0]])

print A


A.characteristic_polynomial()

A.eigenvalues()

# one of the eigenvalues is real, two are complex conjugate pairs and their absolute = 1 => orthogonal matrix

}}}

/* code_ends */

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