Question 308019
You're looking for the angle whose sin={{{sqrt(3)/2}}} and cos={{{1/2}}} or else sin={{{-sqrt(3)/2}}} and cos={{{-1/2}}}. 
Since tan=sin/cos, then tan={{{sqrt(3)}}}.  
{{{60}}} degrees ({{{pi/3}}}) or {{{240}}} degreees ({{{4pi/3}}} ).