Verify the Given Identity $\cos ( x + y ) \cos ( x - y ) = \cos ^ { 2 } x - \sin ^ { 2 } y$

question 44

Essay

Verify the given identity. $\cos ( x + y ) \cos ( x - y ) = \cos ^ { 2 } x - \sin ^ { 2 } y$

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Definitions:

Mastery Goal

An orientation towards learning, where the focus is on gaining new knowledge or mastering a new skill, rather than on demonstrating superior performance compared to others.

Psychological Needs

Fundamental human requirements that are essential for mental well-being, such as the need for love, esteem, and self-actualization.

Motivation

An internal process that stimulates and guides actions to fulfill needs and objectives.

Physical Needs

Basic requirements for human survival including air, water, food, shelter, and sleep.