Abstract
The field equations with variable cosmological and gravitational constants are consider in the presence of perfect fluid for Kaluza-Klein type cosmological model. The exact solutions of the field equations are obtained by using the gamma law equation of state
p
=(
γ
−1)
ρ
in which the parameter
γ
depends on scale factor
R
. The functional form of
γ
(
R
) is used to analyze a wide range of cosmological solution at early universe for two phases in cosmic history:
inflationary phase
and
radiation dominated phase
. The corresponding physical interpretation of cosmological solution are also discussed in the framework of higher dimensional space time.