Angle Sum and Difference, Double Angle and Half Angle Formulas

                    Lesson 1

                                                                                                                                                                          

                                                            Problem:    Find the exact value of sin 52° Cos22° - Cos52°sin22°           

                                                            

                                                            Solution     Sin A Cos B – Cos A Sin B = Sin (A-B)                 

                                                            Step 1:                      

                     

                                                            Solution     Sin 52° Cos22° - Cos52° Sin22° = Sin (52°-22°)                

Step 2:                        

                                                                                         

                                                            Solution     Sin 52° Cos22° - Cos52° Sin22° = Sin (30°)                 

Step 3:                        

 

                                                            Solution     Sin 36° Cos18° - Cos36° Sin18° = 0.5     

Step 4:     

 

                                                            Solution     Answer: 0.5

Step 5:                                                        

Complete                                                                   

                                                                                                                               

                                                             Try two practice problems:  

 

                                                                                 Solve the following:

 

A.

Find the exact value of Sin 48°.

B.

If sin x = 5/9, find Cos (9x).

 

                                                                                               

 

 

 

 

 

        

© Math Worksheets World.com