You cannot. User functions are not supported yet in adv grapher.

[edit to add a bit more detail] The way the advanced grapher works is through knowledge about the functions and the accuracies. It is actually pure floating point and not the HP math library or BCD calculation. In order for user functions/programs to be supported, all the possible commands (or at least a large number of them) need to be linked with the appropriate functions. This could then parse a program/function and determine if all the appropriate information is available and allow user functions.

That would also allow a possible mode where calculations could be done with intervals! This could allow you to do calculations and the errors would automatically accumulate showing the uncertainty for the final result.

TW

*Edited: 4 Nov 2013, 4:37 p.m. after one or more responses were posted*

o.k.