Quote:

I never realized until just recently that the HP-35 exponential function was X^Y. I noticed that it was changed to Y^X on the next models the HP-80 and HP-45. Good thing they did.

Gerardo --

This was covered a few years ago, but I didn't bookmark the discussion.

"Y^X" is indeed more consistent with other operations such as division and subtraction, which perform Y/X and Y-X, respectively.

Unlike the HP-45, the HP-35 lacked a "10^X" key. "X^Y" saved a keystroke over "Y^X" when finding common antilogarithms of a computed value on the HP-35:

(value) 10 X^Y

This is mentioned on the Museum page for the HP-35.

Also, "x raised to the y", like "y over x", may have been considered to be more visually intuitive from the stack representation.

-- Karl

*Edited: 21 Dec 2010, 7:11 p.m. after one or more responses were posted*