Give the Coordinates of the Circle's Center and Its Radius $x ^ { 2 } + y ^ { 2 } - 1 = 0$

Short Answer

Give the coordinates of the circle's center and its radius.
$x ^ { 2 } + y ^ { 2 } - 1 = 0$
Enter your answer using the coordinate notation: (a, b) and r = ....separated with a comma.