[Vertex, Direction] command generates a parabola, with the vertex point and the symetry axis specified.
For the prompt
"Input the vertex of parabola"
, locate a point of the parabola vertex to
generate.
Pressing H key designates if the half part or whole of the parabora be generated.
For the prompt
"Input direciton of the parabola"
, specify a point to define the
symetry axis line of the parabola. The straight from the vertex point of Step1
through the point of this step will be the symetry axis.
For the prompt
"Input terminate point of the parabola."
, locate the end point of the
parabola.