Question

cot390 degrees

Answer 1

Remember that \(\cot\theta=\dfrac{\cos\theta}{\sin\theta}\) and \(390^o=360^0+30^o\); so basically it's just \(30^o\) (Reference angle)

So you have \(\cot(390^o)=\dfrac{\cos(30^o)}{\sin(30^o)}=\cdots~?\)