  Recently, it has been observed that the IIB scattering amplitudes are
compatible with the standard rules of S-duality. Inspired by this observation,
we will find the tree-level S-matrix elements of one Ramond-Ramond and three
open strings by imposing this symmetry on the tree-level S-matrix elements of
one Kalb-Ramond and three open strings. We also find a SL(2, R) invariant form
of the D3-brane effective action containing four gauge fields with derivative
corrections that was derived from one-loop level four-point amplitude. Using
the expansion of the nonlinear SL(2, R) invariant structures, we find the
action with derivative corrections at the level of more gauge fields
