$\"\"$

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(a)

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The identity is $\"\"$ for $\"\"$ .

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Consider $\"\"$ .

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Definition of inverse trigonometry function: $\"\"$ then $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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Substitute $\"\"$ .

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$\"\"$ .

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$\"\"$

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(b)

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The function is $\"\"$ for $\"\"$ .

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Consider $\"\"$

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Apply tangent on each side.

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$\"\"$

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Apply Sum formula of tangent function: $\"\"$ . $\"\"$

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Properties of inverse trigonometry function $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$

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(a) $\"\"$ .

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(b) $\"\"$ .