JEE Main202228 Jul 2022Morning ShiftMathematicsThree Dimensional GeometryActual
The foot of the perpendicular from a point on the circle x 2 + y 2 = 1 , z = 0 to the plane 2 x + 3 y + z = 6 lies on which one of the following curves?
Options
- A6 x + 5 y - 12 2 + 4 3 x + 7 y - 8 2 = 1 , z = 6 - 2 x - 3 y
- B5 x + 6 y - 12 2 + 4 3 x + 5 y - 9 2 = 1 , z = 6 - 2 x - 3 y
- C6 x + 5 y - 14 2 + 9 3 x + 5 y - 7 2 = 1 , z = 6 - 2 x - 3 y
- D5 x + 6 y - 14 2 + 9 3 x + 7 y - 8 2 = 1 , z = 6 - 2 x - 3 y
Correct answer
B. 5 x + 6 y - 12 2 + 4 3 x + 5 y - 9 2 = 1 , z = 6 - 2 x - 3 y
Step-by-step solution
Let the point on the circle be cos θ , sin θ , 0 and foot of the perpendicular from a point on the circle x 2 + y 2 = 1 , z = 0 to the plane 2 x + 3 y + z = 6 be h , k , w , Now using foot of perpendicular formula we get, h - cos θ 2 = k - sin θ 3 = w - 0 1 = - 1 2 cos θ + 3 sin θ - 6 14   . . . . . . 1 ⇒ h = cos θ + - 2 2 cos θ + 3 sin θ - 6 14 ⇒ h = 10 cos θ - 6 sin θ + 12 14   . . . . . 2 Now again from equation 1 we get, k = sin θ