Let ABC be an equilateral triangle with orthocenter at the origin and the side BC on the line x + 2 2y = 4. If the co-ordinates of the vertex A are (α, β), then the greatest integer less than or equal to | + 2 | is
- 5
- 4
- 2
- 3
Answer
(2) 4
Solution
In an equilateral triangle the orthocentre = centroid G = O(0, 0).
Foot of perpendicular D from O to BC (D is the mid-point of BC):
x1 = y2 2 = 41 + 8 = 49
D = ( 49, 8 29 )
G divides AD in the ratio 2 : 1 A = −2D
( , ) = (- 89, - 16 29 )
+ 2 = - 89 - 329 = - 409
| + 2 | = 409 4.44
greatest integer ≤ 4.44 is 4
Answer: (2)