$\"\"$

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(a).

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$\"\"$ is equivalent to $\"\"$ .

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Consider $\"\"$ .

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Property of exponential: $\"\"$ .

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$\"\"$

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Let $\"\"$ .

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$\"\"$ which we considered as $\"\"$ .

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Therefore $\"\"$ is equivalent to $\"\"$ .

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$\"\"$

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(b).

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$\"\"$ is equivalent to $\"\"$ .

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Consider $\"\"$ .

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Trigonometric identiy: $\"\"$ .

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$\"\"$ .

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Let $\"\"$ .

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$\"\"$

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$\"\"$ is equivalent to $\"\"$ .

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$\"\"$

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(a). $\"\"$ is equivalent to $\"\"$ .

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(b). $\"\"$ is equivalent to $\"\"$ .