newRPL: Angles revisited
04-01-2016, 11:46 PM
Post: #20
 emece67 Senior Member Posts: 363 Joined: Feb 2015
RE: newRPL: Angles revisited
(04-01-2016 11:15 PM)Claudio L. Wrote:  [...]
This could be a problem. For example an expression:
'ASIN(A)*ASIN(A)/ASIN(A)'. The user has the settings in DEG, and thinks ASIN will return DEG, so you would expect the result to be let's say 45 or ∡45°.
If the operator associates the right side first:
ASIN(A)*(ASIN(A)/ASIN(A)) = ASIN(A)*1 = ∡45°
but if it associates from the left:
(ASIN(A)*ASIN(A))/ASIN(A) = (pi/4)^2/∡45° = pi/4 (correct, but in radians!)

With the "angle is a number" approach:
ASIN(A)*(ASIN(A)/ASIN(A)) = ASIN(A)*1 = ∡45°
(ASIN(A)*ASIN(A))/ASIN(A) = 45^2 / ∡45° = 45 (not an angle, but at least the same number as expected)
[...]

Not a flaw I've foreseen, but a flaw in any case. I expect all approaches not enforcing unit consistency (not raising errors with ops like scalar / angle) to have such kinds of flaws.

César - Information must flow.
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 Messages In This Thread newRPL: Angles revisited - Claudio L. - 03-31-2016, 06:13 PM RE: newRPL: Angles revisited - Han - 03-31-2016, 06:49 PM RE: newRPL: Angles revisited - Claudio L. - 04-01-2016, 12:50 AM RE: newRPL: Angles revisited - Helix - 04-01-2016, 05:33 PM RE: newRPL: Angles revisited - Han - 04-01-2016, 05:48 PM RE: newRPL: Angles revisited - Claudio L. - 04-01-2016, 06:22 PM RE: newRPL: Angles revisited - Nigel (UK) - 04-01-2016, 06:27 PM RE: newRPL: Angles revisited - emece67 - 04-01-2016, 07:01 PM RE: newRPL: Angles revisited - Claudio L. - 04-01-2016, 11:15 PM RE: newRPL: Angles revisited - emece67 - 04-01-2016 11:46 PM RE: newRPL: Angles revisited - Nigel (UK) - 04-03-2016, 11:05 AM RE: newRPL: Angles revisited - Claudio L. - 04-04-2016, 12:04 AM RE: newRPL: Angles revisited - rprosperi - 03-31-2016, 06:54 PM RE: newRPL: Angles revisited - Claudio L. - 04-01-2016, 12:55 AM RE: newRPL: Angles revisited - rprosperi - 04-01-2016, 02:10 AM RE: newRPL: Angles revisited - Claudio L. - 04-01-2016, 03:47 PM RE: newRPL: Angles revisited - Guenter Schink - 04-01-2016, 09:58 PM RE: newRPL: Angles revisited - Nigel (UK) - 03-31-2016, 08:40 PM RE: newRPL: Angles revisited - Claudio L. - 04-01-2016, 01:12 AM RE: newRPL: Angles revisited - Nigel (UK) - 04-01-2016, 06:20 PM RE: newRPL: Angles revisited - Claudio L. - 04-01-2016, 06:43 PM RE: newRPL: Angles revisited - Claudio L. - 04-01-2016, 07:11 PM RE: newRPL: Angles revisited - SlideRule - 04-03-2016, 04:27 PM RE: newRPL: Angles revisited - Vtile - 04-03-2016, 08:12 PM RE: newRPL: Angles revisited - Claudio L. - 04-03-2016, 11:58 PM RE: newRPL: Angles revisited - Claudio L. - 04-04-2016, 11:52 AM RE: newRPL: Angles revisited - Claudio L. - 04-06-2016, 01:58 PM RE: newRPL: Angles revisited - Nigel (UK) - 04-07-2016, 01:55 PM RE: newRPL: Angles revisited - Claudio L. - 04-07-2016, 05:51 PM RE: newRPL: Angles revisited - Helix - 04-07-2016, 01:04 PM RE: newRPL: Angles revisited - Claudio L. - 04-07-2016, 01:35 PM RE: newRPL: Angles revisited - Francois Lanciault - 05-10-2016, 04:48 AM RE: newRPL: Angles revisited - Claudio L. - 05-10-2016, 02:52 PM

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