Prove that $\sec A(1-\sin A)(\sec A+\tan A)=1$
$LHS =\sec A (1-\sin A )(\sec A +\tan A )$
$=\left(\frac{1}{\cos A }\right)(1-\sin A )\left(\frac{1}{\cos A }+\frac{\sin A }{\cos A }\right)$
$=\frac{(1-\sin A)(1+\sin A)}{\cos ^{2} A}=\frac{1-\sin ^{2} A}{\cos ^{2} A}$
$=\frac{\cos ^{2} A}{\cos ^{2} A}=1=R H S$
Express the trigonometric ratios $\sin A , \sec A$ and $\tan A$ in terms of $\cot A$.
Express $\sin 67^{\circ}+\cos 75^{\circ}$ in terms of trigonometric ratios of angles between $0^{\circ}$ and $45^{\circ}$
Evaluate the following:
$\sin 60^{\circ} \cos 30^{\circ}+\sin 30^{\circ} \cos 60^{\circ}$
Given $\tan A=\frac{4}{3},$ find the other trigonometric ratios of the $\angle A$
Prove the following identities, where the angles involved are acute angles for which the expressions are defined.
$(\sin A+\operatorname{cosec} A)^{2}+(\cos A+\sec A)^{2}=7+\tan ^{2} A+\cot ^{2} A$