Using the basic concept of projective geometry about the intersection of parallel lines, we have developed a new method for choosing integration paths. The integration paths must be decreasing from the starting point to the last point. This condition has remained. To check the correctness, consider a classic example. The advantages of the method are that the method is applicable when the eigenvalues of the matrix are real. The peculiarities of the real eigenvalues of the matrix are that in this case the level lines degenerate at the point of stability change. As a result, the area under consideration is divided into several parts. Carrying out calculations along the selected integration paths, we obtain asymptotic estimates for solutions of singularly perturbed differential equations.