The trigonometric identity is $\"\"$

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Consider LHS is $\"\"$

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Trigonometric properties are

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$\"\"$

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Substitute formulas in LHS and simplify.

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$\"\"$

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$\"\"$

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2.2)

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The trigonometric expression is $\"\"$

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Find the value of $\"\"$

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Rewrite the identity is $\"\"$

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Sum of trigonomeric identity : $\"\"$

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$\"\"$

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2.3)

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The value of acute angles $\"\"$

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Find the value of $\"\"$

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Difference of trigonometic identity : $\"\"$

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Rewrite the angle is

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$\"\"$

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Substitute above values in $\"\"$

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$\"\"$

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2.4)

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The expression is $\"\"$

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Simplify.

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$\"\"$

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2.5)

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The trigonometric equation is $\"\"$

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Find A value.

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Trigonometic properties :

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$\"\"$

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$\"\"$

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