In each of the following, find the centre and radius of the circles.
2x2 + 2y2 – x = 0
The equation of the given of the circle 2x2 + 2y2 –x =0.
2x2 + 2y2 –x =0
(2x2 + x) +2y2 =0
2 
= 0
+ y2 -
= 0
+(y-0)2 =
, which is of the form (x-h)2 + (y-k)2 =r2,
Where, h=
, k = 0, and r= 
Thus, the centre of the given circle is
, while its radius is 
.
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