$\"\"$

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The identity is $\"\"$ .

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Left hand side of the identity is $\"\"$ .

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From the definition of the hyperbolic function $\"\"$ .

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$\"\"$

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Apply formula: $\"\"$ .

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$\"\"$

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Right hand side of the identity is $\"\"$ .

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$\"\"$ .

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$\"\"$

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$\"\"$ .