The exact meromorphic solutions of some nonlinear differential equations

We find the exact forms of meromorphic solutions of the nonlinear differential equations f(n)+q(z)e(Q(z))f((k))=p(1)e(alpha 1z)+p(2)e(alpha 2z), n >= 3, k >= 1, where q, Q are nonzero polynomials, Q equivalent to Const., and p(1), p(2), alpha(1), alpha(2) are nonzero constants with alpha(1) not equal alpha(2). Compared with previous results on the equation p(z)f(3) + q(z)f '' = - sin alpha(z) with polynomial coefficients, our results show that the coefficient of the term f((k)) perturbed by multiplying an exponential function will affect the structure of its solutions.