Problem of Oscillation of mass attached to spring with external force

Homework Statement

A particle of mass m is attached to a spring (of spring constant k) and has a natural angular frequency ω0. An external force. F(t) proportional to cos ωt(ω ≠ ω0) is applied to the oscillator. The time displacement of the oscillator will be?

F=-kx
=-mω2x

F=-ω02x+F0cos ωt