Answer:
The general form of the equation of a circle is (x – h)2 + (y – k)2 = r2
(h, k) is the centre of the circle. r is the radius of the circle.
Substituting the centre and radius of the circle in he general form,
(x – a)2 + (y – a)2 = (√2)2
(x – a)2 + (y – a)2 = 2
The equation of a circle with Centre (a, a) and radius √2 is,
(x – a)2 + (y – a)2 = 2