Let | (60 - ) (60 + ) | 18, [0, 2 ]. Then, the sum of all [0, 2 ], where 3 attains its maximum value, is :
- 6
- 9
- 18
- 15
Answer
(1) 6
Solution
(60 - ) (60 + ) = 14 3
So the condition becomes 14| 3 | 18, i.e. | 3 | 12.
Hence the maximum value is 3 = 12, so 3 = 2n 3 with 3 [0, 6 ]:
= 9, 5 9, 7 9, 11 9, 13 9, 17 9
Sum = 54 9 = 6
Answer: (1)