How do you evaluate arctan((1/sqrt3)?

##arctan(1/sqrt(3)) = pi/6 or 30^o##
This ratio is one of the standard trigonometric triangles:
##arctan## must provide an angle in quadrants one or four; in quadrant four the argument would have needed to be negative.
The ratio ## ((1/2))/((sqrt(3)/2)) = 1/sqrt(3)##
##color(white)(XXXX)##is that of a ##pi/6## angle (as indicated above).