Embibe Experts Solutions for Exercise 3: EXERCISE 3.3

If $\tan \theta =\frac{b}{a}$, then the value of $\cos 2\theta$ is

If $\sin A=\frac{3}{5}$ and $\cos B=\frac{9}{41},0<A<\frac{\pi }{2}$, and $-\frac{\pi }{2}<B<0$ then $\sin \left(A-B\right)$ is equal to

The value of$\mathrm{ }\mathrm{s}\mathrm{i}\mathrm{n}36°\sin 72°\sin 108°\sin 144°$is equal to

$\tan 100°+\tan 125°+\tan 100°\tan 125°$ is equal to

The value of $\frac{\tan 15°}{2-{\sec }^{2}15°}$ is equal to

$\cot 70°+4\cos 70°$ is

If $\sin \theta +\sin 2\theta +\sin 3\theta =\sin \alpha$ and $\cos \theta +\cos 2\theta +\cos 3\theta =\cos \alpha ,$ then $\theta$ is equal to

Prove: ${\cos }^{6}A-{\sin }^{6}A=\cos 2A\left(1-\frac{1}{4}{\sin }^{2}2A\right)$