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anonymous

  • one year ago

Given the sequence -1, 2, -4, 8.... What is the 10th term? Write the number only.

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  1. hybrik
    • one year ago
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    This has a formula to this

  2. anonymous
    • one year ago
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    Well first you have to find the common ratio

  3. Jadeishere
    • one year ago
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    -1 * -2 = 2 2 * -2 = -4 -4 * -2 = 8 8 * -2 = -16 -16 * -2 = 32 you just multiply the last number in the sequence by -2 each time :)

  4. anonymous
    • one year ago
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    okay

  5. hybrik
    • one year ago
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    -16. 32, -64, 128, -256, 512 is the answer [512]

  6. anonymous
    • one year ago
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    There actually is a formula. an = a1*r^(n-1)

  7. hybrik
    • one year ago
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    @ComputerNerd Like i said, its a arithmetic sequence

  8. hybrik
    • one year ago
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    It has a formula

  9. hybrik
    • one year ago
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    a1 is the first number in sequence

  10. anonymous
    • one year ago
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    @hybrik its actually a geometric sequence

  11. anonymous
    • one year ago
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    Write the common ratio for the sequence: 12,6,3,\frac{3}{2},... Write the number only. I'm stuck on this one as well

  12. hybrik
    • one year ago
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    "\frac{3}{2}"?

  13. anonymous
    • one year ago
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    3/2

  14. hybrik
    • one year ago
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    The ratio is 1/2

  15. hybrik
    • one year ago
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    Either you can do this logically or the arithmetic sequence formula

  16. anonymous
    • one year ago
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    Identify the 10th term for the sequence: 12,6,3,\frac{3}{2},... Write the answer as an integer or fraction. I'm stuck on this one as well

  17. anonymous
    • one year ago
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    it's the same pattern as the other

  18. hybrik
    • one year ago
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    @ComputerNerd I noticed when I was using the formula

  19. anonymous
    • one year ago
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    XD

  20. hybrik
    • one year ago
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    3/4, 3/8, 3/16, 3/32, 3/64, 3/128 is the answer, 3/128, by the way, Geometric sequences have to do with Multiplying/Dividing patterns, Arithmetic has to do with Adding / Subtracting

  21. Jadeishere
    • one year ago
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    or you could just do it the easy way @Aliypop and do what I said... Lol @ComputerNerd you don't always need to do the formula if there's a simpler way

  22. anonymous
    • one year ago
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    @Jadeishere It's always best to know the formula. Your method is okay for terms lower in the sequence but would take too long for terms like 100th term.

  23. anonymous
    • one year ago
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    okay

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