$\"\"$

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The equation is $\"\"$ .

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$\"\"$

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Apply sum-to-product identities : $\"\"$ .

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$\"\"$

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Apply zero product property.

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$\"\"$

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$\"\"$

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Solve $\"\"$ .

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$\"\"$

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The general solution of $\"\"$ is $\"\"$ , where $\"image\"$ is an integer.

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$\"\"$

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The solution is $\"\"$ , where $\"image\"$ is an integer.

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$\"\"$

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Solve $\"\"$ .

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$\"\"$ .

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The general solution of $\"\"$ is $\"\"$ , where $\"image\"$ is an integer.

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The solution is $\"\"$ , where $\"image\"$ is an integer.

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$\"\"$

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The solutions are $\"\"$ and $\"\"$ , where $\"image\"$ is an integer.