Computational Method for Solving Singularly Perturbed Delay Differential Equations with Negative Shift

In this paper, a computational method is presented for solving singularly perturbed delay differential equations with negative shift whose solution has boundary layer. First, the second order singularly perturbed delay differential equation is replaced by an asymptotically equivalent first order delay differential equation. Then, Trapezoidal integration formula and linear interpolation are employed to get three term recurrence relation which is solved easily by Discrete Invariant Imbedding Algorithm. The method is demonstrated by implementing several model examples by taking various values for the delay parameter and the perturbation parameter.