[tex]using\ the\ identity\\ \\ 1+tan^2 \theta=sec^2 \theta\\ \Rightarrow tan^2 \theta=sec^2 - 1 \theta\\ \Rightarrow tan \theta= \sqrt{sec^2 \theta-1}\\ \Rightarrow \frac{1}{cot\ \theta} =\sqrt{sec^2 \theta-1}\\ \Rightarrow \boxed{cot\ \theta = \frac{1}{\sqrt{sec^2 \theta-1}} }[/tex]
