Question

If $A={15}^{\circ }$, verify that $4\sin 2A.\cos 4A\sin 6A=1$.

Answer 1

L.H.S$=4\sin (2\times {15}^{\circ })\cos (4\times {15}^{\circ })\sin (6\times {15}^{\circ })$

$=4\sin {30}^{\circ }\cos {60}^{\circ }\sin {90}^{\circ }$

$=4\times \frac{1}{2}\times \frac{1}{2}\times 1$ using the standard values of trigonometric angles

$=1=$R.H.S