KVPY2012MathematicsCircle
Suppose two perpendicular tangents can be drawn from the origin to the circle x ²+ y ²-6 x -2 py +17=0 , for some real p . then | p |=
Options
- A0
- B3
- C5
- D17
Correct answer
C. 5
Step-by-step solution
(x-3)²+(y-p)²=9-17+p² Director circle is (x-3)²+(y-p)²=2 (p²-8 ) Passes through (0,0) array l 9+p²=2 p²-16 p²=25 p= 5 |p|=5 array