Question

The value of $\frac{sin{18}^{\circ }}{cos{72}^{\circ }}$ is ______.

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

Answer 1

The correct option is A

1

$\frac{sin{18}^{\circ }}{cos{72}^{\circ }}$
$=\frac{sin({90}^{\circ }-{72}^{\circ })}{cos{72}^{\circ }}$
$=\frac{cos{72}^{\circ }}{cos{72}^{\circ }}$
$=1$