Question

The value of a if 2X square + 2y square - 3 x + 2 y - 1 = 0 represents a circle and also find its radius

Answer 1

Answer:

Given equation to represents a circle, coefficient of x

2

and y

2

must be same i.e. a=2

So the given equation becomes

2x

2

+2y

2

−3x+2y−1=0

⇒x

2

+y

2

−

2

3

x+y−

2

1

=0

Comparing with general equation of circle, g=−

4

3

,f=

2

1

,c=−

2

1

Hence radius =

g

2

+f

2

−c

=

16

9

+

4

1

+

2

1

=

4

21