A variable circle is described to pass through (1,0) and tangent to the curve Y = tan(tan inverse X) the locus of centre of circle is a parabola whose 1.length of latus rectum is 2 root 2, 2.axis of symmetry does the equation X + Y = 1, 3.vertex has the coordinates (3/4, 1/4), 4.directrix is x - y = 0