回複：請幫忙，一道數學題

來源: 於 2010-09-06 18:17:54 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次

（x+1/x）^2= 3×2
x^2+2 +1/x^2 = 9
x^2 +1/x^2 = 7
(x^2 +1/x^2)^2 = 49
x^4 + 1/x^4 = 47