Question: If $\frac{\pi}{6},\frac{\pi}{2},\frac{5\pi}{6}$and $30^{o},90^{o},150^{o}$, then the number of d...

Question

If $\frac{\pi}{6},\frac{\pi}{2},\frac{5\pi}{6}$ and $30^{o},90^{o},150^{o}$ , then the number of different solutions of 3 $2 - 2\cos^{2}\theta = 3\cos\theta$ is.

Answer 1

Solution

$\Rightarrow$

Where $\theta = 210{^\circ}$ , $330{^\circ}$

Now $1 - \cos 2x + 1 - \cos^{2}2x = 2$

∴ $\cos 2x(\cos 2x + 1) = 0$

$\therefore$ $\cos 2x = 0, - 1$ .

Question: If \(\frac{\pi}{6},\frac{\pi}{2},\frac{5\pi}{6}\)and \(30^{o},90^{o},150^{o}\), then the number of d...

Solution