A community for students. Sign up today!
Here's the question you clicked on:
 0 viewing
 one year ago
Can someone help with this? :)
It is posted below in the comment section so I can use the Equation editor.
 one year ago
Can someone help with this? :) It is posted below in the comment section so I can use the Equation editor.

This Question is Closed

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0dw:1362285707700:dw\[\Sigma \]

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0Find the sum of the arithmetic series! Pleassse help:)

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1\(\huge \sum \limits_{k=1}^nk = \dfrac{n(n+1)}{2}\) and a constant (here, 5) can be taken out of sum sign... :)

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0Where r we getting this formula? I'm confused where to start

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1thats a standard formula that can be used.

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1do you want a formula for sum of terms in arithmetic series ? its equivalent to this formula

terenzreignz
 one year ago
Best ResponseYou've already chosen the best response.0Deriving the formula for an arithmetic series?

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0Yes that is the formula for the arithmetic series. Where do we go from there?:)

terenzreignz
 one year ago
Best ResponseYou've already chosen the best response.0Well, maybe best to use this formula instead \[\huge \sum \limits_{k=1}^nk = \dfrac{n(n+1)}{2}\] It's simpler :D

terenzreignz
 one year ago
Best ResponseYou've already chosen the best response.0So anyway, this sum is just... dw:1362286375802:dw right?

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1ok, i'll mention the sum of arithmetic series formula also, then you choose which one you wanna use, the series will be 5,10,15,20,.... right ? (with n= 100 terms) he 1st term a1 = 5 and there's a common difference of d=5 then the sum formula is : \(S_n = (n/2)(2a+(n1)d)\)

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0terenzreignz...how do you get these expanded form answer? Can u explain that? sorry

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0It is isn't the right answer in the back of the book

terenzreignz
 one year ago
Best ResponseYou've already chosen the best response.0That's just kind of the definition. Or you could say the sigma notation is a compact form of the sum. \[\huge \sum_{k=1}^n=1+2+3+...+(n1)+n\] Basically adding all integers starting at 1 to n.

terenzreignz
 one year ago
Best ResponseYou've already chosen the best response.0\[\huge \sum_{k=1}^nk=1+2+3+...+(n1)+n\] Bloody typo, sorry :)

terenzreignz
 one year ago
Best ResponseYou've already chosen the best response.0So anyway, we can rearrange...dw:1362286994735:dw

terenzreignz
 one year ago
Best ResponseYou've already chosen the best response.0And notice that these terms...dw:1362287037927:dw When added, they all equal n+1

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0what is the final answer? the answer is supposed to be 25,250...I just don't know how to get it

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1did you try any one of the 2 formula i gave u ??

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0Going back to hartnn's response near the beginning. This is like the only formua I'm understanding how to do. \[S _{100}= (100(5 + ?))/2\] I'm just confused how to get that number I didn't fill in? It's supposed to be \[t _{n}\] (which is last term)

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1oh, you need last term ? the general term is 5k to get last term, just put k=100 in general term so, what u get as last term ?

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0So i fill in that question mark spot with 100? Im not sure

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1general term =5k with k=100, last term = 5*100 = 500 _

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0To clarify, this is the formula I am using. \[S _{n}=\frac{ n(t _{1}+ t _{n} )}{ 2 }\]

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0wait how does k =100 again?

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1yup, thats the only other i didn't mention :P because you are summing from k=1 (which is 1st term) to k=100 (WHICH IS LAST TERM)

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1lower limit givs first term, upper limit gives last term

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0ok so 100 is the last term... And why do we multiply it by 5?

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1last value of k is 100 general term = 5k so last term = 5*100

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0and the difference between the numbers would be five right? or is it something else

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1yes, common difference = 2nd term 1st term = 3rd term 2nd term =.... = 105 = 1510 =.... = 5 but thats not required for the formula you are using

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0Oh ok that makes sense now. Maybe you should help me on other problems I post. Your a good help!

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1ok, sure, but did u get 25250 for this one ?

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0Oh wait quick question! What was \[t _{1}\] in this equation

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1t1 is the 1st term index represents which term

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0the index is which part again?

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1index is written as subscript \(\huge t_n\) here n is index and represent which term, t1 = 1st term, t2 =2nd term, and so on

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1yup. as 5 is the 1st term

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0ok im sorry so I'm trying to solve it on paper. And I'm confused again.. how did we get \[t _{n}\] in the formula

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0oh wait my bad! i got it

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1you mean in \(S_n = n (t_1+t_n)/2\) thats a general formula, do you want a derivation of this ?

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0What would happen when I solve for \[t _{n}\] in an equation where n did not equal 1 and it equaled something else?

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1didn't get your question ? do u have specific example for that ? say, if you want to find \(t_5\), then u put n=5 in general term tn

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0dw:1362289579021:dw Like this. N does not equal 1

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1i think u have made up this question ? or is it from your book/notes ?

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0here Ill give you one from the book. dw:1362289721775:dw

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0thats 30 m by the way. It kinda got cut off

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1so, here your 1st term will start from m=10 in 30m and last term you'll get by putting m=20 in 30m

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0so how would i get \[t _{n}\]

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1tm = last term, last m =30 so to get last term tm, put m=30 in general term 30m is this confusing ?

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1general term tm =30m fist term t10 = 3010 (put m=10) last term t20 = 3020 (put m=20)

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0so I would do 30 10 first , and when do I do the 20? i dont know if that makes sense

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0ok lets not do this problem.. Ill ask my teacher on monday..

hartnn
 one year ago
Best ResponseYou've already chosen the best response.1you have formula, you have n, you have 1st term, u have last term....just plug in values! ohh..ok, as u wish

sparky16
 one year ago
Best ResponseYou've already chosen the best response.0Ill be posting other problems so u may help me if u want
Ask your own question
Ask a QuestionFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.