Derivatives on HP 42S

[Albert Chan]

(08-25-2018 05:19 PM)lrdheat Wrote:  This is why, if just 1 function could be added to the HP 42S, I would choose xROOTy !

seems this is trivial to implement.

If x < 0 and y is odd integer, return -(-x) ^ (1/y), else x ^ (1/y)

If you knew y is odd integer, it is even simpler, just check sign of x.
This avoids the extremum search returning complex results.

Just add the check straight into Fx

Edit: complex number don't understand x < 0, may be real part of x instead ?