cos theta = 1 /sec theta so cos theta = 1/2
and 4 cos theta = 4 * 1/2 = 2
sin theta = sqrt ( 1 - cos^2 theta) = sqrt 1 - 1/4) = sqrt (3/4) = sqrt3/2
root 3 sin theta = 3/2
tan theta = sin theta / cos theta = sqrt3 / 2 / 1/2 = 2*sqrt3/ 2 = sqrt3
so the answer is 2 - 3/2 / sqrt3 = 1/2 / sqrt3 = sqrt3 / 6
