Plot Issues with cosh(1/x)

Ah, so you are using Mthcad 15 (or below?)! Good decision!

And from your initial post I got the impression, that you ask how you could manage to just see the plot for x<0. The opposite is the case.

And you sure found a very strange bug here. When I scale down the plot region, sometimes I see the part for x>0, sometimes not. Sometimes I see both branches when I click inside the plot region but when I click outside, the right branch won't show up.

Don't expect PTC to fix that bug.

As Luc already explained, you have more control over the plot if you don't use Mathcads quickplot feature but provide a range for x ( I usually use the variable name x. (note the dot after the x) for plotting so to keep x undefined.)

If you use a very small step width Mathcad choses a very high value for the upper ordinate. You may change the range for the ordinate by typing in more appropriate values (the circled numbers)

But now I realize, the the bug still is shown. With the step width of 0.01 the right branch of the plot still is not shown - thats crazy!

Changing the step width to a lower value (here 0.1) makes the right plot branch show up again:

So I am sorry to say that it seems that you will have to live with that bug.

Either play around with the size of the plot region until you find a good sized region which shows both branches or use a range variable with a suitable stepwidth.