Use the Addition Formulas for Sine and Cosine to Simplify $\cos \left( \theta - \frac { \pi } { 3 } \right) + \cos \left( \theta + \frac { \pi } { 3 } \right)$

question 3

Multiple Choice

Use the addition formulas for sine and cosine to simplify the expression. $\cos \left( \theta - \frac { \pi } { 3 } \right) + \cos \left( \theta + \frac { \pi } { 3 } \right)$

• A) \(\sqrt { 3 }\) \(\cos \theta\)
• B) \(\cos \theta\)
• C) \(\frac { 1 } { 3 } \cos \theta\)
• D) 0
• E) 3 \(\cos \theta\)

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