Step 1: The complex number is $\"\"$ .

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Re-write the expression.

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$\"\"$

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$\"\"$

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De Moivre Theorem: $\"\"$ .

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$\"\"$

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$\"\"$

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Trigonometric identities: $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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Solution:

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$\"\"$