Question

The value of $\frac{sin18°}{cos72°}$

• A. 0.0
• B. 1
• C. 2
• D. Undefined

Answer 1

The correct option is B 1

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