Native mode of trig functions?

[Thomas Klemm]

(10-11-2024 12:38 AM)brouhaha Wrote:  Within +/- pi/2 radians, the trig functions should be very slightly more accurate in radians than in degrees or grads.

It is probably difficult to define what that means since the same number can't be entered exactly in both modes DEG and RAD.
Therefore you have to convert the entry one or the other anyway.

Example

\(
\begin{align}
\cos(36^{\circ})
&= \frac{1+\sqrt{5}}{4} \\
&\approx 0.80901699437\cdots \\
\end{align}
\)

On an HP-41C I get the following results:

DEG
36
COS

0.8090169944

RAD
36
D-R
COS

0.8090169944

5
SQRT
1
+
4
/

0.8090169943

Both results using COS are rounded correctly while the "exact" value using SQRT is not.