$\sin \left( {\frac{\pi }{{10}}} \right)\sin \left( {\frac{{3\pi }}{{10}}} \right) = $
$1/2$
$-1/2$
$1/4$
$1$
The equation ${(a + b)^2} = 4ab\,{\sin ^2}\theta $ is possible only when
Convert $40^{\circ} 20^{\prime}$ into radian measure.
Find the value of the trigonometric function $\cot \left(-\frac{15 \pi}{4}\right)$
If $\frac{{3\pi }}{4} < \alpha < \pi ,$ then $\sqrt {{\rm{cose}}{{\rm{c}}^2}\alpha + 2\cot \alpha } $ is equal to
The product $\left(1+\tan 1^{\circ}\right)\left(1+\tan 2^{\circ}\right)\left(1+\tan 3^{\circ}\right)$ $. .\left(1+\tan 45^{\circ}\right)$ equals