arc (5pi)/3 is in Quadrant IV.
sin ((5pi)/3) = sin ((-pi/3 + (6pi)/3) = sin (-pi/3 + 2pi) =
= sin (-pi/3) = - sin (pi/3) = - sqrt3/2
cos ((5pi)/3) = cos (-pi/3 + 2pi) = cos (-pi/3) = cos (pi/3) = 1/2
tan ((5pi)/3) = (sin)/(cos) = -(sqrt3/2)(2/1) = -sqrt3
cot ((5pi)/3) = 1/(tan) = - 1/sqrt3 = - sqrt3/3
sec ((5pi)/3) = 1/(cos) = 2
csc ((5pi)/3) = 1/(sin) = -2/sqrt3 = - (2sqrt3)/3