Cosmological solutions for model with a 1/H² term

We drive the cosmological solutions of five-dimensional model with $1/H^{2}$ term $(H^{2}\equiv H_{MNPQ}H^{MNPQ})$, where $H_{MNPQ}$ is 4-form field strength. The behaviors of the scale factors and the scalar potential in effective theory are examined.As a consequence, we show that the universe changes from decelerated expansion to accelerated expansion in Einstein frame of the four-dimensional theory.