1. Draw the circle (green line)

2. Draw several (different) chords (blue lines) and their midpoints. Connect the midpoints by a smooth curve (see attachment)

3. The point A is at A(4, 0) (Of course there is a second point A which will yield a different locus - but this part of the question is for you!)

Point is placed on the given circle.

The midpoint of AP has the coordinates

That means the locus of all midpoints is describend by the parametric equation:

4. Determine t from the 1st equation:

Plug in this term into the 2nd equation: