Express the Product as a Sum Containing Only Sines or Cosines

question 168

Multiple Choice

Express the product as a sum containing only sines or cosines.
- $\cos ( 5 \theta ) \cos ( 4 \theta )$

• A) \(\frac { 1 } { 2 } [ \cos ( 9 \theta ) - \cos \theta ]\)
• B) \(\frac { 1 } { 2 } [ \cos \theta + \cos ( 9 \theta ) ]\)
• C) \(\cos ^ { 2 } \left( 20 \theta ^ { 2 } \right)\)
• D) \(\frac { 1 } { 2 } [ \cos ( 9 \theta ) - \sin \theta ]\)

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Definitions:

Territoriality

refers to the behavior by individuals or organisms to claim a physical area, often defending it against others of the same species.

Personal Space

The physical distance individuals prefer to maintain between themselves and others to feel comfortable and secure.

Casual Listening

Listening for enjoyment or entertainment without actively seeking to analyze or interpret the content.

Critical Feedback

Constructive criticism or evaluations intended to help improve one's work, behavior, or performance.