高一數學指數
回答 (2)
2013-10-19 10:12 pm
✔ 最佳答案
正確答案是: 27a過程:
注意看清楚題目: 3a^-1= 3* a^(-1) 和 (9a)^-4/3= 9^(-4/3)* a^(-4/3)
所以式子為: [3* a^(-1) ]^ (1/3) / [ 9^(-4/3)* a^(-4/3) ]
= 3^(1/3)* a^(-1/3) / 9^(-4/3) / a^(-4/3)
= 3^(1/3)* a^(-1/3) * 9^(4/3) * a^(4/3)
= 3^(1/3)* a^1 * 3^(8/3)
= 3^3* a
=27a
答案: 27a (加油~)
2013-10-19 8:26 am
(3 a^-1)^(1/3) ÷ (9 a)^(-4/3)
= (3 a)^(-1/3) ÷ [(9 a)^4]^(-1/3)
= [(9 a)^4]^(1/3) ÷ (3 a)^(1/3)
= (6561 a^4)^(1/3) ÷ (3 a)^(1/3)
= [6561 a^4 ÷ 3a]^(1/3)
= (2187 a^3)^(1/3)
= (3^7 a^3)^(1/3)
= 3^(7/3) a
= 9 ³√3 a
= (3 a)^(-1/3) ÷ [(9 a)^4]^(-1/3)
= [(9 a)^4]^(1/3) ÷ (3 a)^(1/3)
= (6561 a^4)^(1/3) ÷ (3 a)^(1/3)
= [6561 a^4 ÷ 3a]^(1/3)
= (2187 a^3)^(1/3)
= (3^7 a^3)^(1/3)
= 3^(7/3) a
= 9 ³√3 a
參考: 賣女孩的火柴
收錄日期: 2021-04-13 19:46:46
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20131018000015KK04363