f.4 maths (about log)

👨🏻‍🏫 學術台數學

用戶152164

2007-01-29 6:22 am

1) log#(4x-1)=3

2) log@(3x=1)=4

p.s.# = 底係3
@=底係2

更新1:

i 'm sorry for 1 mistake. :P 2) log@(3x=1)=4 [@=底係2]

更新2:

extremely sorry呀...我想打 (3x+1),,,成日都打左係= !! XD

更新3:

Mr.Kwok 你可唔可以教我點樣打3次方同2次方果d呀?? (唔係用^3 or ^2 ...呢d符號代表wor*)

回答 (3)

用戶4366

2007-01-29 6:29 am

✔ 最佳答案

1) log3(4x-1)=3
(4x-1)=33=27
4x=28
x=7
2) log2(3x=1)=4
3x-1=24=16
3x=17
x=17/3

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入會員

2007-01-29 6:05 pm

1....

(4x-1)=3^3=27

4x=28

x=7

2.

3x-1=24=16

3x=17

x=17/3

2007-02-05 12:17:31 補充：
good ans.

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KYO Oscar

2007-01-29 6:32 am

1)log#(4X-1)=3
log(4x-1)/log3=3
log(4x-1)=3log3
log(4x-1)=log3^3
4x-1=27
x=7
2)log@(3x-1)=4
log(3x-1)/log2=4
log(3x-1)=4log2
log(3x-1)=log2^4
3x-1=16
x=17/3
p.s. log@X=k
2^k=x
log2^k=logx
klog2=logx
k=logx/log2
therefore log@x=logx/log2

參考: me

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