若x + 1/x = 7 ，
則(根號)x +1/(根號)x=?
數學問題...........
2007-03-24 2:49 am
回答 (1)
2007-03-24 3:01 am
✔ 最佳答案
若 x + 1/x = 7 求 √x + (1/√x)
(√x + (1/√x))2 = x + 2 + 1/x
因為x + 1/x = 7 則
(√x + (1/√x))2 = 9
√x + (1/√x) = 3 或 √x + (1/√x) = -3
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https://hk.answers.yahoo.com/question/index?qid=20070323000051KK02802