The reason is that symbolic engine does not know what 'rad' or 'm' or any other unit is. Specifically, PTC Mathcad tries to symbolically sin(Pi*rad) and sees 'rad' as undefined symbol and not 1. This is same in Prime 2.0 and 15.0:
When you use :=...= expression, defining 
is the same as definig 
. Similarly, defining 
is the same as definign 
.
The latter is where 15.0 and Prime 2.0 differ. To see advantage of Prime 2.0, consider:
Bottom line: :=...= is _not_ just a convenience for displaying values, but it affects semantics (of symbolic evaluation).
Valery Ochkov wrote:
Thanks, Jakov. I understand it.
But the questin was why all ok is in MC15 and not ok in Pime - see my pictures above.
Again dynamic units?
...:=...=... and ...:=... ...=... must be equal.
The difference is the adding of the (pseudo)unit rad. For numerics its just treated as a scalingfactor with the value 1, but to the symbolics its an unknown variable.
MC15 and Prime react in a different way on pseudounit deg (°). I am still unsure which behaviour has more logic, but unless we get full unit support in symbolics, too, we won't be perfectly happy anyway.
There is a switch in calculation options which promises something like units and constants in symbolic calculations, but it does not change anything. What is this option meant for?
BTW, I am missing Ctrl-Shift-P to get pi and why can't I use the degree sign ° from the keyboard in Prime as I am able to do in MC15?
The latter is where 15.0 and Prime 2.0 differ. To see advantage of Prime 2.0, consider:
A minor advantage if you consider this:
compared to
