A case against the x<>y key

[hansklav]

(05-10-2015 05:16 AM)Den Belillo (Martinez Ca.) Wrote:  I seldom use the X<>Y in hand calculations but have used it in programs more. For instance entering N & E for a point together then the same for another point so as to use the distance formula (or R-P) on them. Surveyors call this inversing and we do it often. I let the program do the ordering and re-ordering and that uses X<>Y each go-around. BTW: the reason surveyors use programs to do something this simple is that we do do it a lot and sooner or later we all fat-finger a key. Data entry itself is enough of a chance for error to creep in.

OK, that is a valid and safe use of the x<>y key.

Also I think when doing several ’stacked‘ power calculations backwards, like in \(9^{2^{3}} \), the use of this key is safe. My point is that when doing the most frequently occurring non-commutative calculations (subtractions and divisions) backwards its use is unsafe in some situations. And you don't have to be a newbie to make a mistake in such situations, as this case proves.

Hans

P.S. The title exaggerates the problem a bit, on purpose ;-)