1.( a +b )^-1/a^-1 + b^-1
2.4^n + 1-16 . 4^n - 1 / 3 . 4^n – 1
有冇人可以幫到我?要詳細步驟 thx
f5數學問題
2007-10-02 1:58 am
回答 (2)
2007-10-02 2:24 am
✔ 最佳答案
1)( a +b )-1/(a-1 + b-1)= [ 1 / ( a + b )] / [ ( 1 / a ) + ( 1 / b )]
= [ 1 / ( a + b )] / [( b + a ) / ab]
= ab / ( a + b )2
2) 4n+1-16(4n-1) / 3 (4n-1)
= 4n+1- ( 42 )( 4n-1 ) / 3 ( 4n-1)
= ( 4n+1 – 4n+1 ) / 3 ( 4n-1 )
= 0 / 3 ( 4n-1 )
= 0
參考: My Maths Knowledge
2007-10-02 2:25 am
1. (a+b)^-1/a^-1 + b^-1
=(1/(a+b))/(1/a + 1/b)
=(1/(a+b))/((a+b)/ab)
=ab/(a+b)^2
2.睇唔明你打乜
=(1/(a+b))/(1/a + 1/b)
=(1/(a+b))/((a+b)/ab)
=ab/(a+b)^2
2.睇唔明你打乜
收錄日期: 2021-04-19 17:13:19
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