F.2 maths question
回答 (2)
2007-10-10 6:49 am
✔ 最佳答案
運用公式 (a-b)^2=a^2-2ab+b^2{ x - (1/x) } ^2
=x^2-2(x)(1/x)+(1/x)^2
=x^2-2+(1/x)^2
=3-2
=1
2007-10-10 8:59 am
Expand [ x - (1/x) ] ^2
= x^2 - 2(x)(1/x) + (1/x)^2
= x^2 - 2 + 1/(x^2)
= [ x^2 + 1/(x^2)] - 2
= 3 - 2 --> since x^2 + 1/(x^2) = 3
=1
hope this helps =)
= x^2 - 2(x)(1/x) + (1/x)^2
= x^2 - 2 + 1/(x^2)
= [ x^2 + 1/(x^2)] - 2
= 3 - 2 --> since x^2 + 1/(x^2) = 3
=1
hope this helps =)
參考: myself
收錄日期: 2021-04-13 13:50:22
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https://hk.answers.yahoo.com/question/index?qid=20071009000051KK04537