How do you evaluate cot((11pi)/6)cot(11π6)?

1 Answer
Sep 25, 2016

cot(11pi)/6 = -sqrt3cot(11π)6=3

Explanation:

cot((11pi)/6)cot(11π6)

Recall the identity cottheta=costheta/sinthetacotθ=cosθsinθ

Using the unit circle, cos((11pi)/6)=sqrt3/2cos(11π6)=32 and sin((11pi)/6)=-1/2sin(11π6)=12

cot((11pi)/6)=frac{sqrt3/2}{-1/2}=sqrt3/2 * -2/1=-sqrt3cot(11π6)=3212=3221=3