If cos theta + cos 2theta + cos 3theta = 0,th | vedclass

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(D) Given the equation: $\cos 	heta + \cos 2	heta + \cos 3	heta = 0$ Grouping the terms: $(\cos 3	heta + \cos 	heta) + \cos 2	heta = 0$ Using th

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Both $(A)$ and $(B)$

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(D) Given the equation: $\cos 	heta + \cos 2	heta + \cos 3	heta = 0$ Grouping the terms: $(\cos 3	heta + \cos 	heta) + \cos 2	heta = 0$ Using the formula $\cos C + \cos D = 2 \cos \frac{C+D}{2} \cos \frac{C-D}{2}$: $2 \cos 2	heta \cos 	heta + \cos 2	heta = 0$ Factoring out $\cos 2	heta$: $\cos 2	heta (2 \cos 	heta + 1) = 0$ Case $1$: $\cos 2	heta = 0$ $2	heta = n\pi + \frac{\pi}{2}$ $	heta = \frac{n\pi}{2} + \frac{\pi}{4}$ Case $2$: $2 \cos 	heta + 1 = 0$ $\cos 	heta = -\frac{1}{2} = \cos \frac{2\pi}{3}$ $	heta = 2m\pi \pm \frac{2\pi}{3}$ Comparing with the options,the general solutions derived are $	heta = 2m\pi \pm \frac{2\pi}{3}$ and $	heta = \frac{n\pi}{2} + \frac{\pi}{4}$. Since the options provided are specific,we identify that $(A)$ and $(B)$ are valid subsets of the general solution set.

If $\cos \theta + \cos 2\theta + \cos 3\theta = 0$,then the general value of $\theta$ is

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