Solution: Given, $2 sin² \theta - cos \theta = 1$ To find:  $\theta = ?$ Now, $2 sin² \theta - cos \theta = 1$ or, $2 sin² \theta = 1 +cos \theta$ or, $sin² \theta = \dfrac{1 +cos \theta}{2}$ or, $sin² \theta = cos²\frac{\theta}{2}$ or, $sin \theta = cos\frac{ \theta}{2}$ Either, $sin \theta = cos\frac{ \theta}{2}$ or, $2 sin\frac{\…