In this method the Es from the previous two iterations can be both positive, negative, or they can have opposite signs.
The shooting method can also be used for solving boundary conditions. The overall approach is the same as with two-point boundary value problems. The second-order (or higher) ODE is converted into a system of first-order ODEs that is solved as an initial values needed for the solution. The solution is then compared with the prescribed boundary conditions, and if the results are not accurate enough, the assumed initial values are modified and the system is solved again. When derivative boundary conditions are prescribed at the endpoint, the calculated of the derivative must be evaluated numerically.