If the line segment joining the points (5, 2) and (2, a) subtends an angle 4 at the origin, then the absolute value of the product of all possible values of a is :
- 4
- 8
- 6
- 2
Answer
(1) 4
Solution
Slopes of OA and OB: m1 = 25, m2 = a2
4 = | m2 - m11 + m1m2 |
| a2 - 251 + a5 | = 1 5a - 4 = (10 + 2a)
a = 143 or a = - 67
| 143 (- 67 ) | = 4
Answer: (1)