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anonymous
 one year ago
Help please??
Find S12 for the series 2 + 5 + 8 +...
anonymous
 one year ago
Help please?? Find S12 for the series 2 + 5 + 8 +...

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0you do see that it's adding 3 each time so the sequence would be starting from 8 would be. 8, 11, 14, 17, 20, 23, 26, 29, 32. and so on.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0ok what is the whole question? cause I just saw that it's adding each number. whats the whole question?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0You want to find the sum to the twelfth term. So you use the formula n/2 * (a + L)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0That is the whole question.

triciaal
 one year ago
Best ResponseYou've already chosen the best response.1this is an arithmetic progression the first term ,a = 2 and the common difference , d = 3 the nth term is a + (n1)d the sum of the first n terms is given by n/2(2a + (n1)d) The question has S12 so I think it needs the sum not when n= 12 as above.

triciaal
 one year ago
Best ResponseYou've already chosen the best response.1@JackJordan can you explain your formula?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0It's standard alevel formula needs no explaining.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0So which ones the right answer? I'm kind of confused.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0How rude of me. Of course it does... you take the sum of an arithmetic series and another, reverse their order. Add then cancel terms. And you will reach the above formula. Can't fit it here but google "sum of arithmetic series"

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0The answer is 222. My calculator malfunctioned earlier on.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0in all honesty so am I, I never seen this formula before. i'm only in 8th grade

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I'm in British College (posh?)... the formula is pretty standard. You can add the numbers up yourself if you want to check.
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