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anonymous

  • one year ago

Write the explicit formula that represents the geometric sequence -2, 8, -32, 128

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  1. freckles
    • one year ago
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    first identify the first term: this is -2 now identify your ratio (just a little more work): divide term by previous term

  2. freckles
    • one year ago
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    That is take any term and its very previous term and divide that term by its previous term

  3. freckles
    • one year ago
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    for example any of these will give your the common ratio: 8/-2 -32/8 128/-32 that is if this is indeed a geometric sequence which the instructions have identified it as one so all of those will be spit out the same number which is....

  4. anonymous
    • one year ago
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    -4

  5. freckles
    • one year ago
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    Now just put everything in \[a_n=\text{ first term} \cdot \text{ (common ratio)} ^{n-1}\]

  6. anonymous
    • one year ago
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    a=-2(-4)^n-1?

  7. freckles
    • one year ago
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    yes the whole n-1 should be a part of the superscript though like this: a_n=-2(-4)^(n-1) or if I type in pretty latex: \[a_n=-2(-4)^{n-1}\]

  8. anonymous
    • one year ago
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    thanks

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