in this article differential transformation method (dtms) has been used to solve neutral functional-differential equations with proportional delays. the method can simply be applied to many linear and nonlinear problems and is capable of reducing the size of computational work while still providing the series solution with fast convergence rate. exact solutions can also be obtained from the kno...

This paper presents using a new modified homotopy perturbation method (NHPM) for solving linear and nonlinear systems of differential-algebraic equations (DAEs) of index one or higher index without index reduction. By using this scheme, explicit exact solution is calculated in the form of a convergent power series with easily computable components. Some examples are given to illustrate the simp...

in this paper, a new analytical method to find a near-optimal high gain controller for the non-minimum phase affine nonlinear systems is introduced. this controller is derived based on the closed form solution of the hamilton-jacobi-bellman (hjb) equation associated with the cheap control problem. this methodology employs an algebraic equation with parametric coefficients for the systems with s...

In this paper, the multistage variational iteration method is implemented to solve a general form of the system of first-order differential equations. The convergence of the proposed method is given. To illustrate the proposed method, it is applied to a model for HIV infection of CD4+ T cells and the numerical results are compared with those of a recently proposed method.

1 Cluster reduction of YDE The elastic and rearrangement processes in the four-particle system with two clusters in the initial and final states can be treated adequately on the base of Yakubovsky differential equations (YDE) [1], [2], [3]

In this study, a Taylor method is developed for numerically solving the high-order most general nonlinear Fredholm integro-differential-difference equations in terms of Taylor expansions. The method is based on transferring the equation and conditions into the matrix equations which leads to solve a system of nonlinear algebraic equations with the unknown Taylor coefficients. Also, we test the ...

Congenital methemoglobinemia is a rare cause of cyanosis. We report a case of a girl, 17 years old with peripheral cyanosis and normal cardio-pulmonary system. She was diagnosed as a case of methemoglobinemia based on findings of polycythemia and HbM band on hemoglobin electrophoresis. We emphasize the importance of this rare entity in the differential diagnosis of cyanosis.

The study of differential equations is useful in to analyze the possible past or future with help of present information. In this paper, the behavior of solutions has been analyzed around the equilibrium points for Gause model. Finally, some results are worked out to exist the stable periodic orbit for mentioned predator-prey system.