Page 343 - DMTH504_DIFFERENTIAL_AND_INTEGRAL_EQUATION
P. 343

Differential and Integral Equation




                    Notes          From (a),
                                                                      p + ay = F ( )                       ...(c)

                                                                      q   ax =
                                   and from (b),

                                                                      p   ay = F ( )                       ...(d)
                                                                      q   ax =
                                   i.e., the two intermediate integrals are

                                                                      p + ay =  ( f q ax )                 ...(1)


                                   and                                p   ay = F (q ax )                   ...(2)

                                   Now since it is not possible to find the values of p and q from (1)  and (2), we proceed as follows.
                                   Suppose  ,   are not constants, but parameters.
                                   Solving (c) and (d),

                                                            b
                                            x =       ,q     .                                             ...(3)
                                                  2a      2
                                                  1
                                                   F
                                            p =    [ ( )  f ( )],                                          ...(4)
                                                  2
                                                  1
                                                    F
                                            y =     [ ( )  f  ( )].                                        ...(5)
                                                  2a
                                   Substituting these values in  dz  p dx q dy ,

                                                  1
                                                                          F
                                                    F
                                            dz =    [ ( )  f  ( )] (d  dx )  [ ( )d  f  ( )d  ]
                                                  4a                   4a
                                                  1
                                                                      f
                                                     F
                                               =    [{ ( )d  F  ( )d  } { ( )d  F  ( )d  }]
                                                  4a
                                                   1                                    1
                                                      F
                                                                                            f
                                                                                                    F
                                                     [{ ( )d  F  ( )d  } { ( )d  f  ( )dB }]  [2 ( ) d  2 ( )d  ].
                                                                        f
                                                   4a                                   4a
                                                  1                          2          2
                                             z =    [ F ( )  f ( )  f ( )  F ( )]  f  ( ) d  F ( )d
                                                  4a                        4a         4a
                                                  1                       2       2
                                                    F
                                               =    [ ( ))(  )  f  ( )(  )]  G ( )  ( )
                                                  4a                      4a     4a
                                                      F ( )  f  ( )  1   1
                                               =                    G ( )   ( )
                                                          2a     2a      2a
                                   or    z   qy =  1 (q ax )  2 (q ax )                          [from (3) and (5)]





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