In the Natural Units environment, the arguments for the trigonometric or hyperbolic functions can be unit-free, in which case the argument is assumed to be given in terms of radians, or multiplied by a unit of angle with the dimension length/length(radius).  An error is returned if the dimension of the argument is not an angle.

If the argument has a unit of angle, it is converted to a free expression in the call to the corresponding global function.  Therefore, a call to sin(7*deg) returns as sin(7/180*Pi), because $1$ degree equals $\frac{\mathrm{\pi }}{180}$ radians.

For other properties, see the global functions in the trig help page.

$\mathrm{with}\left(\mathrm{Units}\left[\mathrm{Natural}\right]\right)\:$

$\sin \left(3\mathrm{deg}\right)$

$\sin \left(\frac{\mathrm{\pi }}{60}\right)$

$\sin \left(180\mathrm{deg}\right)$

$0$

$\cos \left(172.\mathrm{deg}+40.\mathrm{arcmin}+10.32\mathrm{arcsec}\right)$

$\mathrm{-0.9918267366}$