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If a circle whose centre is (-1,1) touches the straight line x+2y=12 then the coordinates of point of contact a) (-7/2,-4)b) (-18/5,-21/5)c) (3,-7)d) (-3,-7)Please provide the whole solution.

If a circle whose centre is (-1,1) touches the straight line x+2y=12 then the coordinates of point of contact a) (-7/2,-4)b) (-18/5,-21/5)c) (3,-7)d) (-3,-7)Please provide the whole solution.

Grade:12

1 Answers

Ankit
18 Points
6 years ago
As the line touches the circle it will be a tangent to the circleNow slope of line or tangent equals to :-1/2Hence slope of the line through (-1,1) and (h,k) will be 2 because tangents are perpendicular to radius drawn, where h,k is the coordinate which are to be find.Now using slope line form( k-1)/(h+1)=2.............¹ eqn.Now h,k lies on the line also so satisfy the eqn of line hence h+2k=12..........² eqn.Solve both eqn and you will get h,kAnswer will be( 6/5,27/5).Check ur options if u directly put the options in the eqn of line they are not satisfying that eqn this proves that ur options are wrong .

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