Question

How do you evaluate `cot (690)`?

Answer 1

`-sqrt 3`

Explanation:

`690=720-30=4(180)-30`.So, `690°` is in the 4th quadrant

and, therefore, `cot` is negative.

And so, `cot 690°=cot(4(180°)-30°)=-cot 30°=-sqrt 3`.