How do I find this summation with an unknown variable at the end? 8+7+6...+(9-1n).
Here's the question:
1. Find the sum:
8+7+6...+(9-1n).
I feel though I should use the formula #sum_(i=1)^nk# (with the "n" in the original question being the "i" in this summation formula). But I'm not sure what my upper limit would be. I also don't know how (or even if I should) solve for the variable in the question. At first, I thought that it was an infinite series and used a different formula, but it didn't work. Could someone help me? Thank you very, very much in advance!
Here's the question:
1. Find the sum:
8+7+6...+(9-1n).
I feel though I should use the formula
1 Answer
Explanation:
The sum of an arithmetic series ( a series which follows the sequence
Here we have:
So,
Given any value of