In this chapter we return to scattering theory and set the foundation
for approximation methods in calculating the scattering amplitude. We also
address the problem of solving the Schrodinger equation for scattering in other
than the coordinate representation. We convert the Schrodinger equation into
an integral equation for the scattering amplitude and discuss ways of solving
such integral equations. In the process we apply the formalism to electronatom
scattering and nucleon-nucleon scattering.
