$\"\"$

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The trigonometric equation is $\"\"$ .

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Subtract $\"\"$ from each side.

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$\"\"$

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Squaring on each side.

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$\"\"$

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Pythagorean identity : $\"\"$ .

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$\"\"$

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Apply reciprocal identity : $\"\"$ .

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

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Find the solutions on the interval $\"\"$ .

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If $\"\"$ , $\"\"$ .

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If $\"\"$ , $\"\"$ .

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Thus, the solutions are $\"\"$ and $\"\"$ on the interval $\"\"$ .

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$\"\"$

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Check :

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The equation is $\"\"$ .

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Substitute $\"\"$ in $\"\"$ .

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$\"\"$

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Since the above statement is true, $\"\"$ is a solution of $\"\"$ .

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Substitute $\"\"$ in $\"\"$ .

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$\"\"$

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Since the above statement is false, $\"\"$ is not a solution of $\"\"$ .

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$\"\"$

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The solution of $\"\"$ is $\"\"$ in the interval $\"\"$ .