Step 1:

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(a)

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The expression is \"\".

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Use the properties of inverse trigonometric function:\"\"

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\"\"

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The exact value of expression \"\"

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Step 2:

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(b)

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The expression is \"\".

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Use the properties of inverse trigonometric function: \"\".

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\"\".

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The exact value of expression \"\".

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Solution:

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(a)

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The exact value of expression \"\"

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(b)

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The exact value of expression \"\" is \"\"