Find all solutions in the interval \( [0,2 \pi) \). \( \sin 2 x \sin x-\cos x=0 \) \( x=\square \) (Type an exact answer, using \( \pi \) as needed. Use a comma to separate answers as needed. Use integers or fractions for any numbers in the expression.) 0 of 1
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Beyond the Answer
To solve the equation \( \sin 2x \sin x - \cos x = 0 \), we can use the identity \( \sin 2x = 2 \sin x \cos x \). This transforms our equation into: \[ 2 \sin x \cos x \sin x - \cos x = 0 \] Factoring out \( \cos x \) gives us: \[ \cos x (2 \sin^2 x - 1) = 0 \] This results in two equations: 1. \( \cos x = 0 \) 2. \( 2 \sin^2 x - 1 = 0 \) For \( \cos x = 0 \), the solutions in the interval \( [0, 2\pi) \) are: \[ x = \frac{\pi}{2}, \frac{3\pi}{2} \] For \( 2 \sin^2 x - 1 = 0 \), we can solve for \( \sin^2 x \): \[ \sin^2 x = \frac{1}{2} \implies \sin x = \pm \frac{1}{\sqrt{2}} = \pm \frac{\sqrt{2}}{2} \] The solutions for \( \sin x = \frac{\sqrt{2}}{2} \) in \( [0, 2\pi) \) are: \[ x = \frac{\pi}{4}, \frac{3\pi}{4} \] And for \( \sin x = -\frac{\sqrt{2}}{2} \): \[ x = \frac{5\pi}{4}, \frac{7\pi}{4} \] Combining all solutions, we get: \[ x = \frac{\pi}{4}, \frac{3\pi}{4}, \frac{\pi}{2}, \frac{5\pi}{4}, \frac{3\pi}{2}, \frac{7\pi}{4} \] Thus, the final answer is: \[ x = \frac{\pi}{4}, \frac{3\pi}{4}, \frac{\pi}{2}, \frac{5\pi}{4}, \frac{3\pi}{2}, \frac{7\pi}{4} \]