require 'trig'
   (sin , cos ,: tan) (1p1 % 4), rfd 45
0.707107 0.707107
0.707107 0.707107
       1        1

   ([ ,. dfr) (arcsin , arccos ,: arctan) 0.5
0.523599      30
  1.0472      60
0.463648 26.5651