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#