What's the domain of G(t) = ln(t^4-1)?

How did you get the answer, the answer in the book says that it's (-infinity, -1) union (1, infinity) but I don't really understand why.

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- Sep 22nd 2008, 03:22 PMdm10Domain Problem
What's the domain of G(t) = ln(t^4-1)?

How did you get the answer, the answer in the book says that it's (-infinity, -1) union (1, infinity) but I don't really understand why. - Sep 22nd 2008, 03:35 PMPlato
For $\displaystyle x \in \left[ { - 1,1} \right]\quad \Rightarrow \quad \ln \left( {x^4 - 1} \right) \mbox{ is meaningless!}$

- Sep 22nd 2008, 03:38 PMdm10
- Sep 22nd 2008, 04:55 PMPlato
- Sep 22nd 2008, 05:39 PMKrizalid
$\displaystyle t^{4}-1=\left( t^{2}+1 \right)\left( t^{2}-1 \right)>0,$ this last 'cause logarithm is defined for numbers greater than zero. Hence, it remains to solve $\displaystyle t^2-1>0$ which gives the expected answer.