In the given figure,find $\tan P - \cot R$.

Evaluate:
$\cos 48^{\circ}-\sin 42^{\circ}$

Consider $\triangle ACB$,right-angled at $C$,in which $AB = 29$ units,$BC = 21$ units and $\angle ABC = \theta$. Determine the values of:
$(i)$ $\cos^2 \theta + \sin^2 \theta$
$(ii)$ $\cos^2 \theta - \sin^2 \theta$

If $\cot \theta = \frac{7}{8},$ evaluate:
$(i) \frac{(1+\sin \theta)(1-\sin \theta)}{(1+\cos \theta)(1-\cos \theta)}$
$(ii) \cot^2 \theta$

Prove that $\frac{\cot A - \cos A}{\cot A + \cos A} = \frac{\operatorname{cosec} A - 1}{\operatorname{cosec} A + 1}$.

$\frac{2 \tan 30^{\circ}}{1+\tan ^{2} 30^{\circ}} = ?$