$\"\"$

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The sound emitted by touching 7 is $\"\"$ .

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(a) Write this sound as a product of sines or cosines.

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$\"\"$

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Apply sum-to-product formula: $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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Apply reduction formula: $\"\"$ .

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$\"\"$ .

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$\"\"$

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(b) Determine the maximum value of $\"\"$ .

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$\"\"$

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Sine function ranges between $\"\"$ .

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The maximum value of sine is $\"\"$ .

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Cosine function ranges between $\"\"$ .

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The maximum value of cosine is $\"\"$ .

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$\"\"$

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$\"\"$ .

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$\"\"$

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(c)

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Graph the function $\"\"$ .

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Graph:

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$\"\"$ .

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$\"\"$

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(a) $\"\"$ .

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(b) $\"\"$ .

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(c) Graph of the function is $\"\"$ :

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$\"\"$ .