$\"\"$

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The equation is $\"\"$ .

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$\"\"$ (Double - angle identity : $\"\"$ )

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$\"\"$ (Subtract cos x from each side)

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$\"\"$ (Simplify)

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$\"\"$ (Take out common factor)

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$\"\"$ (Apply zero product property) $\"\"$

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$\"\"$ (Simplify)

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$\"\"$

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$\"\"$ (Simplify)

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The solutions are $\"\"$ $\"\"$

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The solutions are $\"\"$ .