Pythagorean Identities

                                  Lesson 1

 

                                                            Problem:     Simplify sec x-cos x 

                                                                                              

                                                            Solution      sec x-cos x

                                                            Step 1:                                                                                              

                           

                                                            Solution      (1/cos x)-cos x    (sec x=1/cos x)

                                                            Step 2:           

                            

                                                            Solution      (1-cos2x)/cos x

                                                            Step 3:  

                                                            

                                                            Solution       sin2x/cos x      (1-cos2x=sin2x)

                                                            Step 4: 

                                                           

                                                            Solution        sin x tan x

                                                            Step 5:

Complete      

 

                                                            Try two practice problems:  

 

A.

simplify:

sin x.cos x.tan x + sin x.cos x.cot x

B.

simplify: 2cos2x-1

 

 

 

 

 

 

 

 

 

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