Unexpected Behaviors in Higher- Order Positive Feedback Loops

28 D-4455-25A(0)=2Graph of Exponential BehaviorA(0)=1A(0)=00A(0)=-2-50 1 2 3 4 5 6TimeFigure 17: Vensim Equivalent of Figure 4: Exponential behavior from four differentinitial conditions (second-order positive feedback loop). B(0)=1 in all cases.2Graph of Convergent Behavior10-112B(0)=1A(0)=-12 2 1 21 1-20 1 2 3 4 5 6TimeA: -------------------------------------------------------------- 1 1 1 unitsB: -------------------------------------------------------------- 2 22 unitsFigure 18: Vensim Equivalent of Figure 5:Convergent behavior from initial conditionsA(0)=-1, B(0)=1 (second order positive loop).