SOLUTION: Write the general term of the sequence: 9, 99, 999, ...

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Question 893579: Write the general term of the sequence: 9, 99, 999, ...
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
9.
99=9%2B9%2A10.
999=9%2B9%2A10%2B9%2A10%5E2.
Next would be:
9999=9%2B9%2A10%2B9%2A10%5E2%2B9%2A10%5E3.

9 uses n=1;
9999 uses n=4.


9%2Asum%2810%5E%28i-1%29%2Ci=1%2Cn%29