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Logaritmeoppgåve, 2MX

Posted: 24/03-2007 16:30
by aspic
Hei, sliter litt med denne no:

5^(2X) = 2*5^(-X)

Posted: 24/03-2007 17:33
by Janhaa
[tex]5^{2x}\,=\,2\cdot 5^{-x}[/tex]

[tex](5^{2x})\cdot 5^x\,=\,5^{3x}\,=\,2[/tex]

[tex]lg(5^{3x})\,=\,lg(2)[/tex]

[tex]x\,=\,{1\over 3}\cdot \,{lg(2)\over lg(5)}[/tex]