→ NASAlion : 感謝解答! 11/13 16:58
※ 引述《NASAlion (讓)》之銘言:
: https://i.imgur.com/yiKKmGp.jpg
: 請各位先進幫忙分解,謝謝
a^4 + 4
= (a^2 + 2)^2 - 4a^2
= (a^2 + 2a + 2)(a^2 - 2a + 2)
= [(a + 1)^2 + 1][(a - 1)^2 + 1]
所以
(a + 1)^4 + 4 [(a + 2)^2 + 1][a^2 + 1]
-------------- = --------------------------
(a - 1)^4 + 4 [a^2 + 1][(a - 2)^2 + 1]
[(a + 2)^2 + 1]
= -----------------
[(a - 2)^2 + 1]
所以原式
22^2 + 1
= ------------
2^2 + 1
= 97
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