AP EAMCET2012MathematicsCircle
If the line x+3 y=0 is the tangent at (0,0) to the circle of radius 1 , then the centre of one such circle is
Options
- A(3,0)
- B( -1 10 , 3 10 )
- C( 3 10 , -3 10 )
- D( 1 10 , 3 10 )
Correct answer
D. ( 1 10 , 3 10 )
Step-by-step solution
Given line is x+3 y=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 . Since perpendicular distance from (g, f) to the line is 1 . array ll & +g+3 f 1^2+3^2 =1 & +g+3 f 10 =1 array Taking option (d) i.e., centre = ( 1 10 , 3 10 ) + 1 10 +3 3 10 10 = 10 10 =1 (true)