Question

Which of the following has the same value as cot ${10}^{\circ }$?

• A. tan ${10}^{\circ }$
• B. tan ${80}^{\circ }$
• C. sec ${80}^{\circ }$
• D. sec ${10}^{\circ }$

Answer 1

The correct option is B tan ${80}^{\circ }$

$\because$ cot (${90}^{\circ }-\theta$) = tan $\theta$
$\therefore$ cot ${10}^{\circ }$ = cot (${90}^{\circ }-{80}^{\circ }$) = tan ${80}^{\circ }$