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x


               32.   y(x) –    g(x)+ b cosh(λx)+ b(x – t)[λ sinh(λx) – cosh(λx)g(x)] y(t) dt = f(x).
                            a
                     This is a special case of equation 2.9.16 with h(x)= b cosh(λx).
                        Solution:
                                                           x
                                            y(x)= f(x)+    R(x, t)f(t) dt,
                                                         a
                                                                                   x
                                              G(x)      2  2                 H(x)    G(s)

                       R(x, t)=[g(x)+ b cosh(λx)]  + b cosh (λx)+ bλ sinh(λx)             ds,
                                               G(t)                          G(t)  t  H(s)
                                        x                      b
                     where G(x)=exp     g(s) ds and H(x)=exp   sinh(λx) .
                                      a                      λ
                               x

               33.   y(x) –    g(x)+ b sinh(λx)+ b(x – t)[λ cosh(λx) – sinh(λx)g(x)] y(t) dt = f(x).
                            a
                     This is a special case of equation 2.9.16 with h(x)= b sinh(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 sinh(λx)]  + b sinh (λx)+ bλ cosh(λx)            ds,
                                              G(t)                          G(t)  t  H(s)
                                       x                       b

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

               34.   y(x)+    cos[λ(x – t)]g(t)y(t) dt = f(x).
                            a
                     Differentiating the equation with respect to x twice yields
                                                   x


                                y (x)+ g(x)y(x) – λ  sin[λ(x – t)]g(t)y(t) dt = f (x),      (1)

                                 x                                       x
                                                  a
                                                       x

                                                    2
                                y (x)+ g(x)y(x)  – λ    cos[λ(x – t)]g(t)y(t) dt = f (x).   (2)


                                 xx             x                             xx
                                                      a
                        Eliminating the integral term from (2) with the aid of the original equation, we arrive at
                     the second-order linear ordinary differential equation
                                                        2            2

                                         y xx  + g(x)y  x  + λ y = f (x)+ λ f(x).           (3)

                                                             xx
                     By setting x = a in the original equation and (1), we obtain the initial conditions for y = y(x):
                                        y(a)= f(a),   y (a)= f (a) – f(a)g(a).              (4)


                                                       x
                                                              x
                               x
               35.   y(x)+    cos[λ(x – t)]g(x)h(t)y(t) dt = f(x).
                            a
                     The substitution y(x)= g(x)u(x) leads to an equation of the form 2.9.34:
                                             x
                                     u(x)+    cos[λ(x – t)]g(t)h(t)u(t) dt = f(x)/g(x).
                                           a
                 © 1998 by CRC Press LLC









               © 1998 by CRC Press LLC
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