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Find the sum of the first nine terms 100,−40,16

User Mabuzer
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1 Answer

3 votes

9514 1404 393

Answer:

71.447296

Explanation:

The sequence is geometric with first term 100 and common ratio -0.4. Then the sum of n terms is ...

Sn = 100(1 -(-0.4)^n)/(1 -(-0.4))

and the sum of 9 terms is ...

S9 = 100(1 -(-0.4^9))/(1.4) = 71.447296

Find the sum of the first nine terms 100,−40,16-example-1
User Connor Treacy
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