min/max of atanh(x).

The question : I really need help with min/max of atanh(x).

Really? In what realistic context?

What do you know about tanh(x) and atanh(x)?

Or is it simply that you are confused about the fact, that Mathcad's quickplot isn't showing more of the curve? If you want to see (a liitle bit) more, don't use the quickplot feature but provide your own range variable for x!

Think about what happens to the function at x=+/-1.

PS: Answer to your question: -inf/+inf