Let A = \ [0, 2 ] : 1 + 10 Re ( 2 + i - 3i ) = 0 \. Then A 2 is equal to
- 214 2
- 6 2
- 274 2
- 8 2
Answer
(1) 214 2
Solution
2 + i - 3i + 3i + 3i
= (2 2 - 3 2 ) + 7i 2 + 9 2
1 + 10(2 2 - 3 2 ) 2 + 9 2 = 0
2 + 9 2 + 20 2 - 30 2 = 0
21 2 = 21 2 2 = 1
= 4, 3 4, 5 4, 7 4 in [0, 2 ]
2 = 216(1 + 9 + 25 + 49) = 84 216 = 214 2
Answer: (1)