R. D. Sharma Solutions for Chapter: Trigonometric Ratios, Exercise 5: MULTIPLE CHOICE QUESTIONS (MCQs)

$\sin 2A=2\sin A$ is true when $A=$

$\frac{2\tan 30°}{1-{\tan }^{2}30°}$ is equal to

If $A, B$ and $C$ are interior angles of a triangle $△ABC$, then $\sin \left(\frac{B+C}{2}\right)=$

If $\cos \theta =\frac{2}{3},$ then $2{\sec }^2\theta +2{\tan }^2\theta -7$ is equal to

$\tan 5°\times \tan 30°\times 4\tan 85°$ is equal to

The value of $\frac{\tan 55°}{\cot 35°}+\cot 1°\cot 2°\cot 3°....\cot 90°$, is

In figure, the value of $\cos \varphi$ is

In the figure, $\mathrm{AD}=4 \mathrm{c}\mathrm{m}, \mathrm{B}\mathrm{D}=3 \mathrm{c}\mathrm{m}$ and $\mathrm{CB}=12 \mathrm{c}\mathrm{m}$, find the $\cot \theta$.