Let P be any moving point on the circle ${\mathrm{x}}^2+{\mathrm{y}}^2-2\mathrm{x}=1$ AB be the chord of contact of this point w.r.t. the circle ${\mathrm{x}}^2+{\mathrm{y}}^2-2\mathrm{x}=0$ The locus of the circumcenter of triangle CAB (C being the center of the circle) is