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Started by dasdaa, 16 May 2012 12:23

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#1
dasdaa

Posted 16 May 2012 - 12:23

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Edited by dasdaa, 30 April 2013 - 22:23.

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#2
katkine5

Posted 17 May 2012 - 20:03

I´m not bossy, I just have better ideas.

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http://www.wolframal...9%3D3^%28x-8%29

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#3
Dhannel

Posted 17 May 2012 - 22:20

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Või siis lahenduskäiguga:

16^x=3^x / 3^8
6561*16^x=3^x

Jagad 16^x-ga

6561=(3/16)^x

x=log3/16 6561

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#4
poisonkiller

Posted 18 May 2012 - 09:37

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Ilma kalkulaatorita saab ka (3^8 on jama kirjalikult teha):
2^4x = 3^(x-8)
16^x = 3^x / 3^8
Jagan mõlemad pooled 3^x läbi
(16/3)^x = 1 / 3^8 = 3^-8
Kasutades logaritmi definitsiooni:
x = log_(16/3) 3^-8 = log(3^-8) / log(16/3) = -8 log 3 / (log 16 - log 3) = -8 log 3 / (log 2^4 - log 3) = -8 log 3 / (4 log 2 - log 3)
x = -8 log 3 / (4 log 2 - log 3)
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