數學問題集(2)---找出有理化因式---level1
回答 (1)
2010-08-19 3:38 am
✔ 最佳答案
(1+sqrt2+ sqrt3)(1- sqrt2+sqrt3)(1- sqrt2- sqrt3)(1+sqrt2- sqrt3)= -8
2010-08-18 19:47:23 補充：
( 1+sqrt2+ sqrt3 ) ( 1- sqrt2+sqrt3 )
= ( 1 + sqrt3 ) ^ 2 - 2
= 2 * sqrt3 + 2
(1- sqrt2- sqrt3)(1+sqrt2- sqrt3)
= ( 1 - sqrt3 ) ^ 2 - 2
= 2 - 2 * sqrt3
( 2 * sqrt3 + 2 ) ( - 2 * sqrt3 + 2 )
= 2 ^ 2 - ( 2 * sqrt3 ) ^ 2
= 4 - 12
= -8
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收錄日期: 2021-04-13 17:27:32
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100818000051KK01636