JEE Advanced2006MathematicsParabolaActual
Match the column. Normals at P, Q, R are drawn to y^2=4 x which intersect at (3,0) . Then,
Options
- A(i) (a), (ii) (b), (iii) (d), (iv) (c)
- B(i) (b), (ii) (a), (iii) (d), (iv) (c)
- C(i) (a), (ii) (b), (iii) (c), (iv) (d)
- D(i) (b), (ii) (a), (iii) (c), (iv) (d)
Correct answer
A. (i) (a), (ii) (b), (iii) (d), (iv) (c)
Step-by-step solution
Since, equation of normal is y+x t=2 a t+a t^3 passes through (3,0) . 3 t=2 t+t^3 t=0,1,-1 . P(1,2), Q(0,0), R(1,-2) . Thus, (i) Area of P Q R= 1 2 1 4=2 (ii) Centroid of P Q R= ( 2 3 , 0 ) Equation of circle passing through P, Q, R is aligned & (x-1)(x-1)+(y-2)(y+2)+ (x-1)=0 & 1-4- =0 =-3 & Required equation of circle is x^2+y^2-5 x-1=0 & Centre ( 5 2 , 0 ) and radius 5 2 . aligned