Question 880146
The work I did for this was fairly messy.  I made use of the Unit Circle and the definitions of tangent and cotangent.  Start was done at the inner most nesting and working outward from that.


{{{tan(150)=-1/sqrt(3)}}}  or {{{tan(210)=1/sqrt(3)}}}.  the reference angle for tangent is 30 degree.


{{{cot(x)=1/sqrt(3)=(1/2)/(sqrt(3)/2)=cos(x)/sin(x)}}}, but this would be plus-or-minus, corresponding to 150 degrees or 210 degrees.  This corresponds to 60 degrees or 300 degrees for x.