ϖ= Pi

ϖ0=1.5 ϖ

β=ϖ0/4

γ=0.1

s=NDSolve[{y''[x]+2 β y'[x]+ ϖ0^2  Sin[y[x]]==γ ϖ0^2 Cos[ϖ x],y[0]==0,y'[0]==0},y,{x,0,30}]

Plot[Evaluate[{y[x],y'[x],y''[x]}/.s],{x,0,30},PlotStyle->Automatic]