- #1
demonelite123
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The sum of the first n terms in a certain arithmetic sequence is given by Sn = 3n2 - n. Show that the nth term of the sequence is given by an = 6n - 4.
so far i have done:
Sn = (n / 2) (a1 + an) = 3n2 - n
i solved for a1 + an = 6n - 2
i also have an = a1 + d(n-1).
i don't know what do to next. please help me.
so far i have done:
Sn = (n / 2) (a1 + an) = 3n2 - n
i solved for a1 + an = 6n - 2
i also have an = a1 + d(n-1).
i don't know what do to next. please help me.