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

question 38

Essay

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

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Definitions:

Vacation Pay

Compensation paid to employees for days they are entitled to take off work but choose to work instead or as a benefit for days they are allowed not to work.

Sick Pay

Compensation provided by an employer to an employee who is absent from work due to illness.

Accrual

Accrual accounting is an accounting method where revenues and expenses are recorded when they are earned or incurred, regardless of when the cash transaction occurs.

Footnote Disclosure

Additional notes included in financial statements to provide more detailed information about the company's fiscal status, accounting policies, or individual line items.