×=√10-3 ×*-1/×*= *為平方 1/×*=1÷×*?
回答 (1)
2016-07-23 10:44 am
✔ 最佳答案
x = √10 - 3(x + 3)² = 10
x² - 1 = - 6x
x - 1/x = - 6 ⇔ x + 1/x = 2x + 6
∴ x² - 1/x² = (x - 1/x)(x + 1/x) = - 6(2x + 6) = - 6(2√10 - 6 + 6) = - 12√10
收錄日期: 2021-04-30 21:40:39
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https://hk.answers.yahoo.com/question/index?qid=20160723014224AAWK4w3