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anonymous

  • one year ago

PLEASEEEEE HELPPPPPP Find the sum of a finite geometric sequence from n = 1 to n = 6, using the expression –2(5)n – 1

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  1. anonymous
    • one year ago
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    My options are 1,223 –1,023 –7,812 7,812

  2. anonymous
    • one year ago
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    @welshfella

  3. anonymous
    • one year ago
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    @math1234

  4. welshfella
    • one year ago
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    if its geometric the the nth term = a r^(n - 1) here we have a - = -2 , and r = common ratio = 5 and n is the number of the term so you need to plug thes values into the formula for n terms Sn = a * (r^n - 1) -------- r - 1 n will equal 6

  5. welshfella
    • one year ago
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    * formula for the sum of n terms

  6. welshfella
    • one year ago
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    as i said a = -2 , r = 5 and n = 6

  7. anonymous
    • one year ago
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    so it's -2 times (5^6 - 1) over 5 -1?

  8. welshfella
    • one year ago
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    yep

  9. anonymous
    • one year ago
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    -7,812?

  10. welshfella
    • one year ago
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    yep

  11. anonymous
    • one year ago
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    Thank you so much!!!!!!!!!!!!!!!!!!!

  12. welshfella
    • one year ago
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    yw

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