Question

$\cos \left[{\cot }^{-1}(-\sqrt{3})+\frac{\pi }{6}\right]=$

• A. 0
• B. 1
• C. $\frac{1}{\sqrt{2}}$
• D. $-1$

Answer 1

Answer: (D)

$\cos \left(\pi -\frac{\pi }{6}+\frac{\pi }{6}\right)=\cos \pi =-1$