All solutions of the equation $\cos 4x = -\frac{1}{2}$ can be expressed in the form $\frac{(kn \pm 1) \pi}{6},$ where $n$ is an integer.  Find the positive value of $k.$
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All solutions of the equation $\cos 4x = -\frac{1}{2}$ can be expressed in the form $\frac{(kn \pm 1) \pi}{6},$ where $n$ is an integer.  Find the positive value of $k.$
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All solutions of the equation $\cos 4x = -\frac{1}{2}$ can be expressed in the form $\frac{(kn \pm 1) \pi}{6},$ where $n$ is an integer.  Find the positive value of $k.$
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