This isn't exactly homework but I thought it was too basic to justify putting this post in the general math section.(adsbygoogle = window.adsbygoogle || []).push({});

My question is: why is arcoshx defined as: arcoshx=ln[x+rt(x^2-1)] and not +-ln[x+rt(x^2-1)] ?

Is it simply to keep it as a one to one function? I know that to have an inverse a function should be one to one but why is it not allowed for an inverse function to be 1 to 2 mapping?

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# Quick hyperbolic query

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