Figure 7From: Numerical scheme and dynamic analysis for variable-order fractional van der Pol model of nonlinear economic cycle Phase plot and trajectories (blue line: \(\pmb{x(t)}\) , black line: \(\pmb{y(t)}\) ) for the VOFVDPM with \(\pmb{q_{1}(t)=0.4+0.1\sin(t/50),q_{2}(t)=0.3+2t/3{,}000}\) , \(\pmb{a=0}\) , \(\pmb{\mu=2.5}\) , and \(\pmb{(x(0),y(0))=(1.3,1.2)}\) . Back to article page