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Differential and Integral Equation




                    Notes          and from (2) and (1),

                                                                    1  p x    1      1
                                                              q =    F         F       F ( )          [from (2 )]
                                                                    y   y     y  y   y

                                                                                           1
                                                                 =   . ( )   From (1) and (3),            ...(4)
                                                                     F
                                                                                           y
                                   Now

                                                              dz = p dx + q dy

                                                                 = (    ) x dx  F ( )dy          [from (3) and (4)]


                                                                       x  2
                                                               z =  x       F ( )y k
                                                                       2

                                                                       x  2  1
                                                                 =  x       F    y  ( )
                                                                       2   y  y

                                                                       x 2
                                   or                          z =  x      F      ( )
                                                                       2     y



                                          Example 6: Solve:
                                            5r  6s  3t  2(rt s  2 ) 3  = 0                                 ...(1)

                                   Solution: Comparing it with

                                              Rr Ss Tt U (rt s 2 ) = V

                                   We have                    R = 5, S  6, T  3, U  2, V  3
                                   The  -quadratic will be

                                             2                2
                                             (UV  RT )   SU U    = 0
                                   or                9  2  12  4 = 0

                                   or                   (3   2) 2  = 0

                                                                     2         2
                                                                 =    ,         .
                                                               2     3         3
                                   The intermediate integral will be
                                             U dy   1 T dx  1  . U dp = 0

                                   and        2 R dy U dx  2  . U dq = 0

                                   or             3 dy  3 dx  2dp = 0  and     5dy  3 dx  2 dq  0.




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