Trig

3 cot^2(x) − 1 = 0       add 1 to both sides

3 cot^2 (x)   =  1       divide both sides by 3

cot^2( x)  =   1/3       take the square root of both sides

cot (x)  =  ±√ (1/3)   = 

So

cot (x)  = √ (1/3)      and this happens at  pi/ 3   +  pi* n    where n is an integer

And

cot (x)  =  - √1/3)    and this   happens  at     -pi/3  +  pi*n   where n is an integer