$\frac{2 \tan 30^{\circ}}{1+\tan ^{2} 30^{\circ}}=$
$\cos 60^{\circ}$
$\sin 60^{\circ}$
$\tan 60^{\circ}$
$\sin 30^{\circ}$
Given $\sec \theta=\frac{13}{12},$ calculate all other trigonometric ratios.
Evaluate the following:
$2 \tan ^{2} 45^{\circ}+\cos ^{2} 30^{\circ}-\sin ^{2} 60^{\circ}$
$\sin 2 A=2 \sin A$ is true when $A=$
Evaluate the following:
$\sin 60^{\circ} \cos 30^{\circ}+\sin 30^{\circ} \cos 60^{\circ}$
If $\angle A$ and $\angle B$ are acute angles such that $\cos A =\cos B ,$ then show that $\angle A =\angle B$.