I would like to customize the latex printing of sin, cos, and tan to be more concise. For example, for an expression like sin(delta), instead of the default: \sin(\delta) I would like it to print: s_{\delta} I read section 6.3.2 in the documentation about print methods for functions, in which there was an example for the "abs()" function. I am confused about what needs to go in abs_eval and abs_evalf -- I tried to run that example and wasn't able to get it to compile. If I only want to change the latex printing for sin/cos/tan, but leave everything else the same as the default, what approach should I take? Should I just copy the code from inifcns_trans.cpp into my own, or is there a way to call REGISTER_FUNCTION in a simple way that only modifies the latex printing? ~Luke