JEE Main202225 Jun 2022Morning ShiftMathematicsThree Dimensional GeometryActual
Let Q be the mirror image of the point P 1 , 0 , 1 with respect to the plane S : x + y + z = 5 . If a line L passing through 1 , - 1 , - 1 , parallel to the line P Q meets the plane S at R , then Q R 2 is equal to
Options
- A2
- B5
- C7
- D11
Correct answer
B. 5
Step-by-step solution
Let parallel vector of L = Let Q a , b , c As Q is the mirror image on given plane x + y + z = 5 so a - 1 1 = b - 0 1 = c - 1 1 = - 2 2 - 5 3 a = 3 , b = 2 , c = 3 i.e. Q ≡ 3 , 2 , 3 Let the vector parallel to L be b → So, b → = 1 , 1 , 1 Equation of line L : x - 1 1 = y + 1 1 = z + 1 1 Let point R λ + 1 , λ - 1 , λ - 1 is lying on plane x + y + z = 5 , so, 3 λ - 1 = 5 ⇒ λ = 2 So, point R is 3 , 1 , 1 Hence, Q R 2 = 5