As level math P1 discussion for 9th mayWatch
i found this question about sequences and i don’t seem to know how to continue any further. “The sun of the first n terms of an arithmetic progression is 1/2(3n+7). Find the first term and the common difference of the progression.” This is what i’ve done so far but i’m not sure how to eliminate any of the variables. Any help would be appreciated xx (btw reference is nov.17 paper 12)
So, what do you get if you calculate ?
Yes. So since you are given a formula for , you can find a formula for a_n. Once you have a_n, then is the first term, and should equal the same thing for any choice of k and be the common difference.