I am trying to plot a function on my HP Prime and following instructions in the manual and online but it doesn't work for me. It tells me to go to Apps -> Function, enter the function and hit enter. When I do something simple like ' 2*X' I get a "Error: Bad argument count". When I enter something even simpler like 'X' I get the number 0.3000 in the function field. I have a feeling that somewhere x is defined it picks up that value. Anyways, I can't figure out how to even plot a simple function like 2*x despite reading the manual and looking online. Any help is appreciated.
If your Prime is in RPN Entry Mode (see Home Settings), then your Prime is expecting all entries to be in RPN notation, not algebraic notation. You may enter an algebraic expression in RPN mode by enclosing it in single quotes, like '2*X'. The single quotes key is Shift parentheses.
If you still get that error, or if you are not in RPN mode, then I suspect that you are running into a bug which was removed by HP in a previous firmware update. Which firmware version do you have? (Press Home, Help, Tree, up-cursor, Enter, and look for "Software Version"). If your version's date is older than 2020, run the HP Connectivity Kit on a PC connected to the Internet and let it update its own version and your Prime's firmware version. If that doesn't stop the error from occurring, let us know.
Disclaimer: I don't work for HP. I'm just another happy HP calculator user.