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:

General Journal

A primary accounting record used to record all types of transactions in chronological order before they are posted to individual accounts.

Unearned Items

Revenues received by a company for which the goods or services have not yet been provided or completed.

General Journal

An accounting ledger where all types of transactions are initially recorded.

General Journal

A primary accounting record used to record all types of transactions before they are posted to specific accounts in the general ledger.