value of GRAD angle mode, thought experiment

[Andres]

If the RAD-DEG-GRAD supporting model cost $ 100, then the RAD-DEG supporting model should cost $ 90... :-)

From time to time I found GRAD useable, but not as much as to pay a large difference for it. Is easy to do a scale operation ( 10 / 9 *) or (9 / 10 *) to convert GRAD "to" and "from" DEG.

I recall using GRAD mode in a simple game which ran on the HP25. It goes more or less as:

An object moves in a square board with X and Y coordinates ranging from 0 to 100. If, when updating the position of the object after an iteration, it hit the boundaries, it bounces back. If the calculator is set in GRAD mode, the following sequence can be used to implement the bouncing:

RCL X coordinate (or Y coordinate)
RCL deltaX (or deltaY)
+

SIN
ASIN
COS
ACOS

STO X coordinate (or Y coordinate)

(For clarity, in the example I'm not using 2-D vector addition by means of the summation function, which the original game did)