All functions of the profile are available in this box in the alphabetical order. The only condition is, that the function must be depending on some variable(s). The function selected here is the main one. It means that automatic vertical positioning tracks just a curve of this function. This function is the only one, which definition domain is highlighted. The undefined area of the function is drawn red at the level of zero.Notice: There is a way to show a constant function. You can add and immediately subtract some variable to the constant, but it is necessary to disable the automatical solving (menu-SET-SOLVE-off).
For example 5+x-x or ext+x-x will be considered as functions of x (supposing the x is an existing variable and the solving is off).
