Use the Fundamental Identities to Simplify the Expression $2 \cos 8 x \cos 2 x$

question 308

Multiple Choice

Use the fundamental identities to simplify the expression.
- $2 \cos 8 x \cos 2 x$

• A) \(\sin 10 x + \sin 6 x\)
• B) \(\cos 10 x + \cos 6 x\)
• C) \(\cos 6 x - \cos 10 x\)
• D) \(\frac { 1 } { 2 } ( \cos 10 x + \cos 6 x )\)

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