This is an initial attempt to improve your answer. First eliminate errors in the first three lines, and focus on a small `t` up to 1.2. Beyond that there is a singularity/stiff system. This is for the small `t` range! Clear[x]; r = 1; sol = NDSolve[{Derivative[1][x][t] - 1 - r*x[t] - x[t]^2 == 0, x[0] == 0}, x, {t, 0, 1.2}] Plot[Evaluate[x[t] /. sol], {t, 0, 1.2}] ParametricPlot[Evaluate[{x[t], Derivative[1][x][t]} /. sol], {t, 0, 1.2}] [![enter image description here][1]][1] First plot shown here. [1]: https://i.sstatic.net/KTdjb.png