推 eric911116 : 感謝! 08/02 20:22
※ 引述《eric911116 (TCFSH)》之銘言:
: https://i.imgur.com/2I2bfcp.jpg
: 想請教圖上的兩題,有算過但算不出答案來。謝謝大家!
44.
2(1 - k)sin(theta) = 1 + k
=> |1 + k|/|1 - k| <= 2
=> (k - 1/3)(k - 3) >= 0
=> k <= 1/3 or k >= 3
=> |k - 5/3| >= 4/3
選(C)
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