How to find the value of sin ( 112 1 2 ) using the double or half angle formula?

Question

How to find the value of             sin              (        112                  1          2                )             using the double or half angle formula?

trackrunner92yuy · Accepted Answer

As             sin              (                  90          ⊕                θ        )              =          cos      θ                  sin              (                  90          o                +                              (            22                          1              2                        )                    o                )              =                            cos                      (            22                          1              2                        )                          o                  Now as       2                  cos        2            A        -    1    =          cos      2        A  , if       A    =                  (        22                  1          2                )            o      ,       A    =          45      o      and       2                  cos        2                              (          22                      1            2                    )                o              -    1    =                            cos          45                o            =              1              2            or       2                  cos        2                              (          22                      1            2                    )                o              =    1    +          1              2              =                            2                +        1                    2            and                     cos        2                              (          22                      1            2                    )                o              =                            2                +        1                    2                  2                      =                  2        +                  2                    4                                    cos                      (            22                          1              2                        )                          o            =                                2          +                      2                              2      Therefore                               sin                      (            112                          1              2                        )                          o            =                                2          +                      2                              2

How to find the value of sin ( 112 1 2 ) using the double...

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