Derivatives on HP 42S

[lrdheat]

Hi Thomas,

When I try to XEQ the function in it's own little program, say "FX" within the derivative program sandwiched between the 2 complex commands, the correct answer is returned with a minute complex component. (I wish to have the function that I am finding the extremum point as it's own program that the derivative program can call...this allows me to then run the function program to evaluate f(x) of the extremum)

I can then do a switch of x and y stack levels, but was wondering why I cannot simply get the real part of the extremum to be delivered to the x stack level.

Richard