Conchoidal motion
The motion is determined by the envelope o of the line b and path c of point C. Construct the fixed centrode of the motion and the path of point E on line b.
The centrodes are special curves which are tangent to one another at each instant of the motion and there is no slipping during the motion. The motion is obtained by rolling (without slipping) the moving centrode in the moving plane on the fixed centrode in the fixed plane.
Task:
The motion is determined by the point envelope (b) of the line b and path of point A. Construct the fixed centrode of the motion and the path of point Q on line b, |QA| = q.