HP Prime not Computing Correctly

[Nigel (UK)]

(02-23-2023 06:01 PM)pschlie Wrote:  I guess I simply believe that when wishing to presume angles are expressed in degrees, then select degrees (which in-turn equates pi = 180, with trig functions similarly assuming degree operands); when wishing to presume angles are expressed in radians (which includes the formula A = pi*r^2 to calculate the area of a circle; and -1 = e^(i* pi) for example, with trig functions similarly assuming radian operands), then select radians as the preferred angular mode (which in-turn equates pi = 3.14...); I don't really see a problem, or anything which would be unexpected; pi is an angular value.

I don't agree that the formulae \(A = \pi r^2\) (or \(C = \pi d\)) assume anything about angular units. In the first, \(\pi\) is the ratio of two areas; in the second, \(\pi\) is the ratio of two lengths. I'm sure you know that values for \(\pi\) slightly greater than 3 go back to antiquity; radians, I believe, only go back 200-300 years. You could argue, if you wished, that circular area should be measured in different units than "square" area, and circular length in different units than "straight" length, but I'm not sure why you would wish to do this.

Perhaps I'm misunderstanding what you are suggesting. I can see why setting (for example) \(\sin\pi = 0\), etc., if \(\pi\) is expressed symbolically, might be useful. No-one has any business to be calculating the sine of pi degrees! But angular modes would still be needed, and perhaps it is least confusing to leave things as they normally are?

Nigel (UK)