Page 14 - modul trigonometri bilingual
P. 14

C


                           Example 1.1
                                                                                              6 cm
                        Look at the ABC triangle on the side.
                        Specify a value of 2 sin A tan C.
                                                                    A                         B
                                                                                 8 cm

                          Alternatife Solutions


                        Ac side length:


                                     2
                                              2
                              = √     +     
                                         2
                                  2
                            = √8 + 6
                            = √64 + 36                                                         C
                            = √100
                            = 10                                        hypotenuse
                                                                                         6 cm  opposite
                        Note the triangle from angle A looks
                                                                                   8 cm
                        like the following triangle.                  A                         B
                                                                                  adjacent
                                                           6
                        sin    =                 =      =                                      C
                                 ℎ                          10


                        The side of the triangle from the
                                                                        hypotenuse
                        angle C looks like the following                                 6 cm  adjacent
                        triangle.                                                 8 cm
                                                                      A                         B
                                                          8                      opposite
                        tan    =             =       =
                                                         6

                        Thus:

                                               6     8
                        2 sin    tan    = 2 ×     ×
                                               10    6

                                       2 × 48      8
                                    =           =
                                          60       5
                                                           8
                        So, the value of 2 sin A tan C is
                                                           5









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