A vertical asymptote occurs when function limit goes to infinity.
cot is reciprocal of tangent.
cot = 1/tan, Find where tan = 0, since 1/0 goes to infinity.
tan(a) = 0 when a = 0,pi
Now Apply coefficient inside cot function.
x/2 = 0,pi
x = 0, 2pi
Therefore, vertical asymptotes occur when x = 0 or 2pi