Mehdi Nadjafikhah - School of Mathematics, Iran University of Science and Technology, Narmak, Tehran, ۱۶۸۴۶--۱۳۱۱۴, Iran
Mansoureh Mirala - Department of Mathematics, Payame Noor University, Tehran ۱۹۳۹۵--۴۶۹۷, Iran
Mohamad Chaichi - Department of Mathematics, Payame Noor University, Tehran ۱۹۳۹۵--۴۶۹۷, Iran

The approximate equation for the forced fractional oscillator is obtained by approximation of the Riemann- Liouville fractional derivatives. And the approximate symmetries and conservation laws of the forced fractional oscillator are derived when the system is in resonance.

forced fractional oscillator, approximate symmetry, resonance, approximate conservation law