45e  pi f* 180e f/     \ radians

cr fdup  fsin f.       \ also available: fsincos ( r -- sin cos )
cr fdup  fcos f.
cr fdup  ftan f.
cr fdup fasin f.
cr fdup facos f.
cr      fatan f.       \ also available: fatan2 ( r1 r2 -- atan[r1/r2] )