Do not use a calculator in this question.

In the right-angled triangle, \(AB=3+\sqrt3\) and \(BC=3-\sqrt3\).

(i) Find \(\tan ACB\) in the form \(r+s\sqrt3\), where \(r\) and \(s\) are integers.

(ii) Find \(AC\) in the form \(t\sqrt u\), where \(t\) and \(u\) are integers and \(t\neq1\).