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3. Numerical Linear Algebra                                      107

                U 6=68.0000 - 0.0000i
                      37.0000 - 0.0000i
                      20.0000 - 0.0000i

                         th
              Therefore 6  term is 20 as expected (see the sequence).

           8.       COMPUTATION OF EXPONENTIAL
                    OF THE MATRIX


           Let A be the  matrix,  which can be diagonalizable  using Eigen matrix as
                     A
                  -1
           A=EDE  . e  can be  computed using series expansion as given below.

               A
                                   3
                           2
              e = I + A +(A )/2! +(A )/3!+…..

                                                            -1
                      -1
                                                      -1
                                                -1
                                    -1
                              -1
              = I +EDE  +(EDE  EDE ) /2! +(EDE  EDE  EDE )/3!+…

                                              3 -1
                           -1
                  0 -1
                                  2 -1
              = ED E +EDE  + (ED E )/2! +(ED E )/3! +…

                                                  4
                                                             -1
                                2

                   0

                                         3
              = E[D  + (D/1! )+(D /2!) + (D  /3!) +(D  /4!) +…] E

                     -1
                  D
              = E e  E
           8.1      Example
                                  -1
              A =    1   1         = EDE
                        1   0

               0.5257   -0.8507           -0.6180        0                0.5257   -0.8507
              -0.8507   -0.5257            0                 1.6180      -0.8507   -0.5257

                        A
              Therefore e is computed as

                 D
              E e  E -1     =

                                            0
               0.5257   -0.8507           e -0.6180                          0.5257   -0.8507
                                                              -
              -0.8507   -0.5257            0             e 1.6180            0.8507    0.5257
                                                      -


              =  3.7982    2.0143
                 2.0143    1.7839
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