Thank you for your answer. I explain further: I actually got display({plot([P(op(TA[1]), op(TA[nops(TA)]))]), seq(plot([P(op(TAlink[k]))]), k = 1 .. nops(TAlink))}); where P, TA, TAlink are functions. This display gives us a closed graph, built by a sequence of parametric functions. And my aim is to calculate the area delimited by these parametric functions. I was thinking by proceeding with rectangle approx, so i need to calculate the coordinates of intersection points of vertical line, and limits of this plot. Thank you, Lartichou.

Thank you for your answer. I explain further: I actually got display({plot([P(op(TA[1]), op(TA[nops(TA)]))]), seq(plot([P(op(TAlink[k]))]), k = 1 .. nops(TAlink))}); where P, TA, TAlink are functions. This display gives us a closed graph, built by a sequence of parametric functions. And my aim is to calculate the area delimited by these parametric functions. I was thinking by proceeding with rectangle approx, so i need to calculate the coordinates of intersection points of vertical line, and limits of this plot. Thank you, Lartichou.