Let the parabola y=x2+px-3, meet the coordinate axes at the points P, Q and R. If the circle C with centre at (-1,-1) passes through the points P, Q and R, then the area of PQR is :
- 4
- 6
- 5
- 7
Answer
(2) 6
Solution
The centre lies on the perpendicular bisector of chord PQ (on the x-axis): + 2=-1 p=2.
[figure]
x2+2x-3=0 P(1,0), Q(-3,0); R(0,-3)
Base PQ=4, height OR=3
Area = 12 4 3=6
Answer: (2)