JEE Main202329 Jan 2023Evening ShiftMathematicsThree Dimensional GeometryActual
The plane 2 x-y+z=4 intersects the line segment joining the points A ( a ,-2,4) and B (2, ~b ,-3) at the point C in the ratio 2: 1 and the distance of the point C from the origin is 5 . If a b<0 and P is the point ( a - b , b , 2 ~b - a ) then CP ^2 is equal to:
Options
- A17 3
- B16 3
- C73 3
- D97 3
Correct answer
A. 17 3
Step-by-step solution
Given points are: A ( a , - 2 , 4 ) and B ( 2 ,   b , - 3 ) Point C divides the line segment joining points A and B in the ratio 2 : 1 , so C ≡ a + 4 3 , 2 b - 2 3 , - 2 3 Also, C lies on 2 x - y + 2 = 4 , therefore 2 a + 8 3 - 2 b - 2 3 - 2 3 = 4 ⇒ 2 a + 8 - 2 b + 2 - 2 = 12 ⇒ a - b = 2       . . . . 1 Also, O C = 5 ⇒ a + 4 3 2 + 2 b - 2 3 2 + 4 9 = 5 ⇒ a 2 + 8 a + 16 + 4 b 2 + 4 - 8 b = 45 ⇒ a 2 + 8 a + 4 b 2 - 8 b = 25       . . . 2 Solving 1