數學問題集(54)---數學雜題(一)
2010-10-07 2:37 am
回答 (5)
2010-10-07 4:47 am
✔ 最佳答案
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2010-10-06 20:47:33 補充：
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2010-10-07 7:14 am
(x + y)^2 = 1^2
x^2 + 2xy + y^2 = 1
xy = -1/2
(x + y)(x^2 + y^2) = 1*2
x^3 + y^3 + xy(x + y) = 2
x^3 + y^3 = 5/2
(x^2 + y^2)^2 = 2^2
x^4 + 2(xy)^2 + y^4 = 4
x^4 + y^4 = 7/2
(x^3 + y^3)(x^4 + y^4) = (5/2)(7/2)
x^7 + y^7 + (xy)^3(x + y) = 35/4
x^7 + y^7 = 71/8
x^2 + 2xy + y^2 = 1
xy = -1/2
(x + y)(x^2 + y^2) = 1*2
x^3 + y^3 + xy(x + y) = 2
x^3 + y^3 = 5/2
(x^2 + y^2)^2 = 2^2
x^4 + 2(xy)^2 + y^4 = 4
x^4 + y^4 = 7/2
(x^3 + y^3)(x^4 + y^4) = (5/2)(7/2)
x^7 + y^7 + (xy)^3(x + y) = 35/4
x^7 + y^7 = 71/8
2010-10-07 3:24 am
1) 2(a^2 + ab + b^2)^2
2010-10-07 2:57 am
2010-10-07 2:40 am
3)
5/9 ~ 56 %
5/9 ~ 56 %
收錄日期: 2021-04-13 17:33:29
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20101006000051KK00981