Basic Identities and Their Use

      The following basic identities should be memorized.

                      Reciprocal Identities

                 


                    Quotient Identities

               


               Identities for Negatives

                


               Pythagorean Identities

          

                      

                      

Proving Identities
To verify, or to prove, an identity means to prove that both sides
of an equation are equal for all replacements of the variables for
which both sides are defined.
The proof might involve using basic identities or other verified identities,
and algebraic operations such as multiplication, factoring, combining and
reducing fractions, and so on.

          See Examples 1 – 7, pages 525 – 530, of the textbook.


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