The square of diameter of the circle having tangent at (1,1) as x+y−2=0 and passing through (2, 2) is ……

Given equation of tangent at P(1,1) is x+y−2=0 Then, normal equation at P is x−y=0⇒ Diameter will be x−y=0 And Q(2,2) lies on x−y=0⇒ It is other end of diameter ∴ Length of diameter =PQ=1+1=2 Square of the length of the diameter = 2 Therefore, the correct answer is 2.00