  Classical subleading soft graviton theorem in four space-time dimensions
determines the gravitational wave-form at late and early retarded time,
generated during a scattering or explosion, in terms of the four momenta of the
ingoing and outgoing objects. This result was `derived' earlier by taking the
classical limit of the quantum soft graviton theorem, and making some
assumptions about how to deal with the infrared divergences of the soft factor.
In this paper we give a direct proof of this result by analyzing the classical
equations of motion of gravity coupled to matter. We also extend the result to
the electromagnetic wave-form generated during scattering of charged particles,
and present a new conjecture on subsubleading corrections to the gravitational
wave-form at early and late retarded time.
