Find an angle between 0 and 2pi that is coterminal with the resulting angle.
First I need to verify that you are rotating clockwise 2 times by a measure of (5pi)/6.
A clockwise rotation would be subtracted from the original angle.
(-5pi)/6 - (5pi)/6 - (5pi)/6 = (-15pi)/6 = -2((3pi)/6
Each rotation around the axis is 2pi so -2((3pi)/6 = (-3pi)/6 = (-pi)/2