Since each term is 1 2 1 2 times the previous, this is a geometric sequence. Each term is 1 2 1 2 times the previous term. In the sequence, the change from 4 to 2 is a multiplication by 1 2 1 2, as is the next jump, from 2 to 1, as is the next from 1 to 1 2 1 2. In a geometric sequence, though, each term is the previous term multiplied by the same specified value, called the common ratio. So, you add a (possibly negative) number at each step. We know what a sequence is, but what makes a sequence a geometric sequence? In an arithmetic sequence, each term is the previous term plus the constant difference. This process exhibits exponential growth, an application of geometric sequences, which is explored in this section. Every 8 years, the investment would double again, so after the third 8-year period, the investment would be worth 2 × 2 × ( 2 × $ 400 ) = $ 1,600 2 × 2 × ( 2 × $ 400 ) = $ 1,600. After another 8 years (for a total of 16 years) the investment would be twice its value after the first 8 years, or 2 × ( 2 × $ 400 ) = 2 × ( $ 400 ) = $ 800 2 × ( 2 × $ 400 ) = 2 × ( $ 400 ) = $ 800. For example, if you invest $200 in an account with an 8-year doubling time, then in 8 years the value of the account will be double the starting amount, or 2 × $ 200 = $ 400 2 × $ 200 = $ 400. A shorter doubling times means the investment gets bigger, sooner. One of the concerns when investing is the doubling time, which is length of time it takes for the value of the investment to be twice, or double, that of its starting value.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |