Just to clarity to simplify

(1+√3) / (1-√3) to multiple (1+√3) / (1+√3) OR (1-√3) / (1-√3)

both seems to result the same answer, I'm not sure but people usually multiple by (1-√3) / (1-√3) ?

Thanks

What you want to use is

(a-b)(a+b) = a^2-b^2
and you do not want square roots in the denominator
so
multiply top and bottom by
(1+√3)
and you will have 1-3 = -2 in the denominator