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6.8. Equations With Nonlinearity of General Form

                                            b

                 6.8-1. Equations of the Form  G(···) dt = F (x)
                                            a
                       b


               1.       y(x)f t, y(t) dt = g(x).
                      a
                     A solution: y(x)= λg(x), where λ is determined by the algebraic (or transcendental) equation

                        b

                     λ   f t, λg(t) dt =1.
                       a
                         b
                         k


               2.       y (x)f t, y(t) dt = g(x).
                      a
                     A solution: y(x)= λ[g(x)] 1/k , where λ is determined from the algebraic (or transcendental)
                                  b
                     equation λ k  f t, λg 1/k (t) dt =1.
                                a
                       b


               3.       ϕ y(x) f t, y(t) dt = g(x).
                      a
                     A solution in an implicit form:

                                                 λϕ y(x) – g(x) = 0,                        (1)
                     where λ is determined by the algebraic (or transcendental) equation
                                                               b


                                        λ – F(λ)=0,    F(λ)=     f t, y(t) dt.              (2)
                                                               a
                     Here the function y(x)= y(x, λ) obtained by solving (1) must be substituted into (2).
                        The number of solutions of the integral equation is determined by the number of the
                     solutions obtained from (1) and (2).

                         b

               4.       y(xt)f t, y(t) dt = A.
                      a
                     1 . Solutions: y(x)= λ k , where λ k are roots of the algebraic (or transcendental) equation
                      ◦
                        b

                     λ   f(t, λ) dt = A.
                       a
                     2 . Solutions: y(x)= px + q, where p and q are roots of the following system of algebraic
                      ◦
                     (or transcendental) equations:
                                      b                       b

                                       tf(t, pt + q) dt =0,  q  f(t, pt + q) dt = A.
                                     a                       a
                                        ¯

                     In the case f t, y(t) = f(t)y(t), see 6.2.2 for solutions of this system.
                     2 . The integral equation has some other (more complicated) solutions of the polynomial
                      ◦
                                     k
                     form y(x)=  n    B k x , where the constants B k can be found from the corresponding system
                               k=0
                     of algebraic (or transcendental) equations.
                      ◦
                     4 . The integral equation can have logarithmic solutions similar to those presented in item 3 ◦
                     of equation 6.2.2.



                 © 1998 by CRC Press LLC









                © 1998 by CRC Press LLC
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