Question6. $\frac{\sec 2 \theta}{4}\left[\frac{\cos 8 \theta-1}{\cos 4 \theta-1}\right]=\cos 2 \theta$ எனக் காட்டுக.

Studdy Solution
Multiply both sides by $2\cos 2\theta$ to eliminate the fraction:
$$\cos 4\theta + 1 = 2\cos^2 2\theta$$
Use the identity $\cos 4\theta = 2\cos^2 2\theta - 1$:
$$2\cos^2 2\theta - 1 + 1 = 2\cos^2 2\theta$$
Both sides are equal, proving the equation.
The equation is verified as true.