A case against the x<>y key

[Dave Britten]

I tried doing this on my 20S just for giggles to see if it would give the correct result, but kept messing up something (usually involving parentheses) toward the end of the formula. It makes one really appreciate how easy it is to correct mistakes in RPN, e.g. I accidentally forgot to multiply by 8!, and a quick LAST X - LAST X got me right back to where I could. After a couple tries at getting it right on the 20S, I gave up and went back to the 32S.