Question 481733
As the angle is 11pi/6, then its reference angle is 2pi-11pi/6= pi/6

Further, as the reference angle lies in IV quadrant, hence 

cot(11pi/6)= -cot(pi/6) = -cos(pi/6)/sin(pi/6)
-((sqrt3)/2)/(1/2)
-(sqrt3/2)*(2/1)
-(sqrt3)