If x-(1/x)=a, express x^3-(1/x^3) in terms of a .Give your answer in the simplest form.
the ans. is a^3+3a
please show clear steps.thx
rational functions
2010-03-24 11:51 pm
回答 (1)
2010-03-25 12:13 am
✔ 最佳答案
x - 1/x = a(x - 1/x)^3 = a^3
x^3 - 3(x^2)(1/x) + 3(x)(1/x)^2 - 1/x^3 = a^3
x^3 - 3x + 3/x - 1/x^3 = a^3
x^3 - 1/x^3 = a^3 + 3x - 3/x
x^3 - 1/x^3 = a^3 + 3(x - 1/x)
x^3 - 1/x^3 = a^3 + 3a
收錄日期: 2021-04-21 22:09:43
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