AP EAMCET Engineering 2012 Solved Paper

Given line is x+3y=0.
∴ Slope of a line =−

1

3

Let the centres of circle be (+g,+f).
We know that, the perpendicular drawn from the centre to the tangent is equal to radius.Since perpendicular distance from (g,f) to the line is 1 .
∴

+g+3f

√12+32

=1
⇒

+g+3f

√10

=1
Taking option (d) i.e., centre =(

1

√10

,

3

√10

)
∴

+ 1 √10 +3× 3 √10

√10

=

10

10

=1 (true)