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Domains of ln(hyperbolic functions) help

So the question is write down the maximal domain of ln(cosh x ) now graphically I've seen online that the answer is around 710.
However, I'm struggling in proving this mathematically. And some help would be appreciated.
I haven't come across hyperbolic functions before, although I know what they represent, in terms of e.

Help would be appreciated.
Original post by joe1545
So the question is write down the maximal domain of ln(cosh x ) now graphically I've seen online that the answer is around 710.
However, I'm struggling in proving this mathematically. And some help would be appreciated.
I haven't come across hyperbolic functions before, although I know what they represent, in terms of e.

Help would be appreciated.


I suggest that you sketch the graphs of log(x)\log(x) and of cosh(x)\cosh(x). Then, where are the problems going to be with log(x)\log(x)? Does the range of cosh(x)\cosh(x) intersect with this "problem set"?

BTW, I'm not at all sure where you get 710 from...

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