JEE Main20249 Apr 2024Morning ShiftMathematicsStraight LinesActual
A ray of light coming from the point P(1,2) gets reflected from the point Q on the x -axis and then passes through the point R(4,3) . If the point S(h, k) is such that PQRS is a parallelogram, then h k^2 is equal to :
Options
- A70
- B80
- C60
- D90
Correct answer
A. 70
Step-by-step solution
Image of P wrt x -axis will be P^ (1,-2) equation of line joining P^ R will be y-3= 5 3 (x-4) Above line will meet x -axis at Q where aligned & y =0 x = 11 5 & Q ( 11 5 , 0 ) aligned PQRS is parallelogram so their diagonals will bisects each other aligned & 4+1 2 = 11 5 + h 2 & 2+3 2 = k +0 2 & h = 14 5 & k =5 & hk ^2= 14 5 5^2=70 aligned