\"\"

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(a)

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The trigonometric function is \"\", \"\".

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Since \"\" lies in quadrant I, \"\" is also lies in quadrant I.\"\"

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(b)

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Find \"\".

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Using half - angle formulas: \"\".

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Substitute \"\" in above formula.

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\"\"

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\"\"       (Since angle \"\" is in quadrant I)

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\"\"

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Find \"\".

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Using half - angle formulas: \"\".

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Substitute \"\" in above formula.

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\"\"

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\"\"      (Since angle \"\" is in quadrant I)

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\"\"

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Find \"\".

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Using half - angle formulas: \"\".

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From Pythagorean theorem, \"\".

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Substitute \"\" and \"\" in above formula.

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\"\"

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\"\".

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\"\"

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(a) \"\" lies in quadrant I.

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(b) \"\", \"\" and \"\".