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anonymous
 one year ago
Find the sum of the arithmetic sequence.
10, 7, 4, 1, 2, 5, 8
11
70
0
7
anonymous
 one year ago
Find the sum of the arithmetic sequence. 10, 7, 4, 1, 2, 5, 8 11 70 0 7

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Goshhh cant you add them just add them you get 7

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh so all i do is add?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0that's what I'd do since they're listed

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0what if they give me only 4 terms and tell me to find the sum of the first 9

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0nevermind all you do is find the difference then find the first 9 terms then add them right?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Find the sum of the first 9 terms of the sequence. Show all work for full credit. 2, 7, 16, 25, ...

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0for that one they probably want to see you use the formulas. Can you come up with a equation for a_n using the formula?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Well ye but if you should use equations same thing so d=+3 and they are 7 terms so n=7 S(7)=7/2 (10+8)=7/2(2) =7

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0this one. where you have to find d and a_1 \[a_n=a_1+d(n1)\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0This is a straight arithmetic sequence guys no need for this d is simply d=Un+1 Un

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0yes. and they want the sum of the first 9 so now find a_9

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0a9 would = 70 right?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0yes. Now for the sum use this formula \[S_n=\frac{ n }{ 2 }(a_1+a_n)\] so \[S_9=\frac{ n }{ 2 }(a_1+a_9)\]

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so the sum would =306

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0The sum of the first 9 is 18 S9=n/2 ( 2a1+(n1)d = 9/2 (20+24) =36/2 =18

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Oh sorry used another sequence

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@joyraheb different set of numbers from the sequence at the very top

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ok good because i was about to say, i thought i finally understood this then that messed me up hahaha

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Oh ok so d=9 so S9=4.5(14+90)= 342 right?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0no s9= (9/2)(2+(70)) = 306

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0because of this equation Sn=n/2(a1+an) @joyraheb
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