
Re: [中學] 空間向量 1題

: 感謝
令AE = k
AC * (AD + k) = 0
=> AD * AC + k * AC = 0
(AD + k) * (AB + k) = -1
=> |k|^2 + k * AC + AB * AD = -1
=> |k|^2 = -1 + AD * AC - AB * AD
= -1 + 3 = 2
選(2)
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推
03/18 21:17,
9月前
, 1F
03/18 21:17, 1F
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