HP-35’s x^y Why?

[J-F Garnier]

(11-03-2021 02:37 AM)robve Wrote:  I strongly suspect that a dedicated key for the y'th root of x (or the x'th root of y with Sharp) surely indicates that negative x with odd y'th roots are supported, e.g. (-27)^1/3 returns -3.

Yeap.

(11-03-2021 03:46 AM)robve Wrote:  HP-35s:
ALG mode: (-128)^INV(7) ERROR
RPN mode: 7 1/x 128 (-) y^x ERROR

... these calculators have an n-th root key except the Ti-25.

But why, oh why HP-35s did you fail?

Here, I don't follow you. Why not using the nth-root key?
With it, the 35S doesn't fail. No need to create a new artificial weakness of this machine.

An additional benefit of the nth-root is a marginally improved accuracy.
Example on Saturn-based HP machines:
125^(1/3) = 4.9999...
but XROOT(125,3)=5 exactly.
(unless Albert finds a counter example :-)

J-F