Question

Evaluate using your knowledge of the unit circle:cot 120°

Answer 1

We are asked to evaluate cot 120,

`\begin{gathered} \cot 120^0=(1)/(\tan 120^0) \\ 120^0\text{ falls in the second quadrant. } \\ \tan 120^0=-\tan (180^0-120^0)=-\tan 60^0 \\ \end{gathered}`
`\Rightarrow\cot 120^0=-(1)/(\tan 60^0)=-\frac{1}{\sqrt[]{3}}=-\frac{\sqrt[]{3}}{3}`