Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

ll asked in Science & MathematicsMathematics · 2 days ago

Use the formula for the sum of the first n terms of the geometric sequence, and then state the indicated sum?

81+9+1+1/9+1/81

s5=

1 Answer

Relevance
  • ?
    Lv 7
    2 days ago
    Favorite Answer

    81, 9, 1, 1/9, ...

    a_n = 9^(3 - n) 

    S5 

    = 81 + 9 + 1 + 1/9 + 1/81 

    = 7381/81

    = 91.12345679012345...

Still have questions? Get your answers by asking now.