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infinitemoes
 2 years ago
Please help! What is the sum of the series? 20 on top and n1 on the bottom of ∑(5n)
infinitemoes
 2 years ago
Please help! What is the sum of the series? 20 on top and n1 on the bottom of ∑(5n)

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infinitemoes
 2 years ago
Best ResponseYou've already chosen the best response.1no it's a n1 on the bottom of the sigma.

mrbarry
 2 years ago
Best ResponseYou've already chosen the best response.1\[\sum_{n1}^{20} (5n)\]

infinitemoes
 2 years ago
Best ResponseYou've already chosen the best response.1yes exactly like that

mrbarry
 2 years ago
Best ResponseYou've already chosen the best response.1It should be n=1 I am certain. If we did this "manually" we would have 4 + 3 + 2 + ... Right?

mrbarry
 2 years ago
Best ResponseYou've already chosen the best response.1This is an arithmetic sequence b/c we are adding 1 over and over. There is a formula to solve this, Arithmetic Series Formula. Do you know it?

infinitemoes
 2 years ago
Best ResponseYou've already chosen the best response.1I think I got the answer. 110

mrbarry
 2 years ago
Best ResponseYou've already chosen the best response.1Let's see. The formula says: 1/2 the number of items times (first term + last term) 1/2 (20) (4 + 15) 10 (11) Good job.

mrbarry
 2 years ago
Best ResponseYou've already chosen the best response.1You are welcome. All done? Thanks for the medal.

infinitemoes
 2 years ago
Best ResponseYou've already chosen the best response.1Well I do have a couple more questions, but I'm gonna post them separate to this post.
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