Tangents are drawn from the point P(2,2) to the circle x2+y2=1, touching the circle at A and B. Then equation of circumcircle of △PAB is
Tangents are drawn from the point P(1, 8) to the circle x2+y2−6x−4y−11=0 touch the circle at the point A and B, then equation of the circumcircle of the triangle PAB is