I am dealing with second order linear differeantial equations for RLC and forced RLC circiuts.

I am having trouble with plotting a solution curve in the phase plane.

> restart;

with(plots); with(DEtools);

L := 10; R := 20; C := 1/100;

de1 := diff(x(t), t) = y(t);

de2 := L*(diff(y(t), t))+R*y(t)+x(t)/C = 0;

DEplot({de1, de2}, [x(t), y(t)], t = 0 .. 5, [[x(0) = 10, y(0) = 0]], stepsize = 0.5,