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x


               38.   y(x) –    g(x)+ b cos(λx) – b(x – t)[λ sin(λx) + cos(λx)g(x)] y(t) dt = f(x).
                            a
                     This is a special case of equation 2.9.16 with h(x)= b cos(λx).
                        Solution:
                                                          x

                                            y(x)= f(x)+    R(x, t)f(t) dt,
                                                         a
                                               G(x)     2  2               H(x)     x  G(s)
                         R(x, t)=[g(x)+ b cos(λx)]  + b cos (λx) – bλ sin(λx)           ds,
                                               G(t)                        G(t)  t  H(s)
                                                             b
                                        x
                     where G(x)=exp     g(s) ds and H(x)=exp   sin(λx) .
                                      a                      λ
                               x

               39.   y(x) –    g(x)+ b sin(λx)+ b(x – t)[λ cos(λx) – sin(λx)g(x)] y(t) dt = f(x).
                            a
                     This is a special case of equation 2.9.16 with h(x)= b sin(λx).
                        Solution:
                                                          x

                                            y(x)= f(x)+    R(x, t)f(t) dt,
                                                         a
                                               G(x)     2  2               H(x)     x  G(s)
                         R(x, t)=[g(x)+ b sin(λx)]  + b sin (λx)+ bλ cos(λx)            ds,
                                               G(t)                        G(t)    H(s)
                                                                                 t
                                       x                       b

                     where G(x)=exp     g(s) ds and H(x)=exp –  cos(λx) .
                                                              λ
                                      a

                 2.9-2. Equations With Difference Kernel: K(x, t)= K(x – t)

                             x

               40.   y(x)+    K(x – t)y(t) dt = f(x).
                            a
                     Renewal equation.
                      ◦
                     1 . To solve this integral equation, direct and inverse Laplace transforms are used.
                        The solution can be represented in the form

                                                          x
                                            y(x)= f(x) –   R(x – t)f(t) dt.                 (1)
                                                        a

                     Here the resolvent R(x) is expressed via the kernel K(x) of the original equation as follows:

                                                    1     c+i∞    px
                                                             ˜
                                             R(x)=           R(p)e  dp,
                                                   2πi
                                                        c–i∞
                                              ˜
                                             K(p)                 ∞     –px
                                      ˜
                                                         ˜
                                     R(p)=         ,    K(p)=      K(x)e   dx.
                                                ˜
                                            1+ K(p)             0
                     •
                       References: R. Bellman and K. L. Cooke (1963), M. L. Krasnov, A. I. Kisilev, and G. I. Makarenko (1971),
                     V. I. Smirnov (1974).
                 © 1998 by CRC Press LLC









               © 1998 by CRC Press LLC
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