newRPL: Angles revisited

[Nigel (UK)]

(04-01-2016 05:48 PM)Han Wrote:  

(04-01-2016 05:33 PM)Helix Wrote:  Why?
For me, 10°+10°+10° = 3x10° = 30°, and 30°/3 = 10°.
I think that an angle multiplied or divided by a constant (a real number) should be an angle.

My guess would be ambiguity in interpreting the real number -- is it a constant multiplier, or did the user intentionally leave off the ° but still wanted to actually have degrees. In the former, you have what is essentially the same as your examples; in the latter, you would be looking at fractions of a circle (as one possible interpretation). With addition, there is only one reasonable meaning of something like 30° + 3. The only thing you can really add to angle (or perhaps temperature) is a change in angle (temp), so there is no ambiguity.

I think that it is so useful to be able to divide an angle by two, or three (etc.) that division (or multiplication) by a real number should leave the result as an angle. If the intent is to divide one angle by another then the divisor can be explicitly tagged as an angle.

So 30D 3 / gives 10D; 30D 3D / gives 10.

I agree that 30D 3 / is ambiguous - does 3 mean "3" or "3D" or "3R" in radians mode? - but I think that this is the best way to resolve the ambiguity.

Nigel (UK)