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