[ Eq(Derivative(x1, t), (1*k40*k31*x1*(1 - x1/k32) + (-1)*k40*k36*k34*x1/(k35 + k33*x1) + (-1)*k40*k1*x1*x4*(1 + k25*k38) + (-1)*k40*k2*x1*x3/(1 + (x4/k3)**2 + (k37/k29)**2)*(1 + k27*k38))/k40),
  Eq(Derivative(x2, t), ((-1)*k40*k4*x2*x4*(1 + k25*x4) + (-1)*k40*k5*x2*x3/(1 + (x4/k3)**2 + (k37/k29)**2)*(1 + k27*k38) + 1*k40*k11*x4 + (-1)*k40*k6*x2)/k40),
  Eq(Derivative(x3, t), (1*k40*k17*(k16*x2 + k13*x1 + k14/(1 + (k38/k26)**2)*x3 + k15*x4)/(1 + (k37/k30)**2)/(k18 + (k16*x2 + k13*x1 + k14/(1 + (k38/k26)**2)*x3 + k15*x4)/(1 + (k37/k30)**2)) + (-1)*k40*k19*x3)/k40),
  Eq(Derivative(x4, t), ((-1)*k40*k11*x4 + 1*k40*k9*(k8*x2 + k7*x1)/(1 + (k37/k28)**2)/(k10 + (k8*x2 + k7*x1)/(1 + (k37/k28)**2))/(1 + (k38/k24)**2) + (-1)*k40*k12*x4*x3/(1 + (x4/k3)**2 + (k37/k29)**2))/k40) ]