Question

Which of the following angles can be used to evaluate cot(-210°)

Answer 1

Answer:

-$\sqrt{3}$

Step-by-step explanation:

We know that cot (-x)  = -cot x

                therefore  cot(-210) = -cot(210)

                                     and we know that cot (180+x) = cot(x)

                              [since 210 lies in  third quadrant therefore its positive ]        

                     therefore  cot(180+30 ) = cot 30

 so here in the question

     cot(-210) = -cot(210)  = - cot (30)

                                         = -$\sqrt{3}$

     

Answer 2

Cot (- 210º) = - √3 so 30°