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theequestrian
 3 years ago
Algebra II help !
(picture)
What did I do wrong..?
I always thought at the bottom, where n=? you used the number that the sequence started with, which in this case was 5 & then to the right of the E shape went the general term.
Where have I messed up?
theequestrian
 3 years ago
Algebra II help ! (picture) What did I do wrong..? I always thought at the bottom, where n=? you used the number that the sequence started with, which in this case was 5 & then to the right of the E shape went the general term. Where have I messed up?

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msayer3
 3 years ago
Best ResponseYou've already chosen the best response.1if you are going from 5 to inf, the first of sequence would be 25

msayer3
 3 years ago
Best ResponseYou've already chosen the best response.1does that make sense? so the series shouldn't start from 5

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0It kind of does, I suppose. How do you get that? Just by multiplying 5 by itself? & sorry it took me so long to respond, my internet is not getting along with this site.. grr.

msayer3
 3 years ago
Best ResponseYou've already chosen the best response.1the site is going through some upgrading and maintenance so it's no biggie  now, you should first look at the bounds of summation which is to infinity indicating it's going positively up. so when you have it set from 5 to positive infinity, you are going from 5, 4, 3...

msayer3
 3 years ago
Best ResponseYou've already chosen the best response.1if you put that as n into the equation and see what values you get, it would be more clear for you

msayer3
 3 years ago
Best ResponseYou've already chosen the best response.1so on that note, you should consider changing lower bound of summation with what you have as summation equation

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0So @msayer3 what your saying is that I should put what is on the right of the E looking thing should go on the bottom? But I thought that was the general term? & I thought the general term went to the side?

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0& sorry for all the questions..

Ihm
 3 years ago
Best ResponseYou've already chosen the best response.2Umn, I would disagree with msayer. The upper term is not the value of the out put but the value of n. n is the index of the term. So in the example; the index of 10 is 2 and the index of 20 is four. You would want dw:1344369052834:dw. The E thing is a capital sigma. Look up bigsigma notation on wikipedia for more.

msayer3
 3 years ago
Best ResponseYou've already chosen the best response.1no, what you have in the right side of summation sign looks correct. Just consider changing n = 5 statement which is what's called the lower bound of summation

msayer3
 3 years ago
Best ResponseYou've already chosen the best response.1@lhm that's where I was getting at

msayer3
 3 years ago
Best ResponseYou've already chosen the best response.1sorry i get my terminologies confused

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0Wait, so what does all that mean?

msayer3
 3 years ago
Best ResponseYou've already chosen the best response.1so simply, your index term for summation is starting at wrong point

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0& that is my bottom number, right?

Ihm
 3 years ago
Best ResponseYou've already chosen the best response.2Ah. msayer would be right if you were doing something like sum all the values from 1 to 10 (where it would have just 10 above and i=1 below and i on the right).

msayer3
 3 years ago
Best ResponseYou've already chosen the best response.1@Ihm i think we are thinking the exact same thing

Ihm
 3 years ago
Best ResponseYou've already chosen the best response.2I just reread your first statement. I think so too. >.<

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0Okay, since y'all know are on the same page now, Lol, what did I do wrong...?

Ihm
 3 years ago
Best ResponseYou've already chosen the best response.2As msayer said, your index term is off. Try expanding the sum a bit like this:\[5*1+5*2+5*3...\] where 1,2,3,etc are values of n. Remember that n increases by 1 each step. Here's the layout: \[\sum_{startingindex}^{endingindex} whatever*index\] Try playing around with the starting index. There rest of what you have is fine.

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0Okay, but what should I try? Like there has to be a method to the madness.

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0@msayer3 @Ihm Not to bug y'all, but I don't know what to try

Ihm
 3 years ago
Best ResponseYou've already chosen the best response.2Wait. are you summing the terms in the list or just producing the list?

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0Just producing the list? I'm honestly not sure. I don't have to add anything so I assume make a list.. Does that make sense/answer your question..?

Ihm
 3 years ago
Best ResponseYou've already chosen the best response.2Ok. (I find the question oddly worded). Either way you can look at it like this: make some of the series and write the indexes underneath each term. 5,10,15,20,25  term  index take the bit to the right of the sigma and plug in the starting index (below the sigma) for n. If it doesn't match the first term, then it's wrong. Just plug in things like 5, 0, 10, and the like. That will show you how changing the starting index will screw with your sum.

Ihm
 3 years ago
Best ResponseYou've already chosen the best response.2If you fill in the index part of the table above, the first index is your starting index.

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0So by doing this I find out what goes underneath the stigma?

Ihm
 3 years ago
Best ResponseYou've already chosen the best response.2Yes and why it's important.

theequestrian
 3 years ago
Best ResponseYou've already chosen the best response.0I'm sorry, I'm still kind of confused... How will plugging in the numbers give me what goes below? Like I thought it was always what you started with, like your starting number. & Thanks for continuing to help me, I really appreciate it. Like you have no idea.

Ihm
 3 years ago
Best ResponseYou've already chosen the best response.2You needn't plug stuff in to find the right answer it's just something I thought might help you grasp what it is we're doing when we change the starting index.  Think of the index (below the sigma) as an address. Each element in the series has its own, unique address. The starting index can be any number but it always points to the first element in the series, the next element will have an address that is one more than the starting index, and so on.

Ihm
 3 years ago
Best ResponseYou've already chosen the best response.2The important thing is the starting index isn't the first number in the series, it's the /address/ of the first number.
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