Simplify the Expression Algebraically $\cos ( 6 x + 9 y ) + \cos ( 6 x - 9 y )$

question 15

Multiple Choice

Simplify the expression algebraically.
$\cos ( 6 x + 9 y ) + \cos ( 6 x - 9 y )$

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Definitions:

Subgoals

Intermediate objectives or steps devised to make the process of achieving a main goal more manageable and attainable.

Analogies

Comparisons made between two things for the purpose of explanation or clarification.

Models of Concepts

Theoretical frameworks used to understand how humans categorize information, form concepts, and apply these concepts to everyday life.

Cultural Bias

A predisposition to interpret and judge other people's cultures by the standards and values of one's own culture.