Page 416 - 35Linear Algebra
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                            as a demonstration of changing basis.
                               Since this was a linear systems problem, we can try to represent what’s in
                            the barrel using a vector space. The first representation was the one where
                            (x, y) = (apples, oranges):




                                                 Oranges


                                                           (x, y)










                                                                              Apples






                            Calling the basis vectors ~e 1 := (1, 0) and ~e 2 := (0, 1), this representation would
                            label what’s in the barrel by a vector



                                                                           x
                                                    ~x := x~e 1 + y~e 2 = ~e 1  ~e 2  .
                                                                             y
                            Since this is the method ordinary people would use, we will call this the
                            ‘‘engineer’s’’ method!
                               But this is not the approach nutritionists would use. They would note the
                            amount of sugar and total number of fruit (s, f):


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