$\"\"$

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The trigonometric equation is $\"\"$ and the interval is $\"\"$ .

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Factorize the quadratic equation.

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$\"\"$

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Since the range of the inverse tangent function is $\"\"$ ,

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Obtain two solutions in the interval $\"\"$ .

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$\"\"$

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$\"\"$

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If $\"\"$ , then the general solution is $\"\"$ , where $\"image\"$ is an integer.

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

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$\"\"$

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If $\"image\"$ , then

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$\"\"$ ,

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If $\"image\"$ , then

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$\"\"$ ,

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If $\"image\"$ , then

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$\"\"$ .

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Thus, the solutions are $\"\"$ , $\"\"$ ,

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and $\"\"$ in the interval $\"\"$ .

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$\"\"$

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

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and $\"\"$ in the interval $\"\"$ .